ML040070165
| ML040070165 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 12/17/2003 |
| From: | Lagergren W Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 1-RR-05 | |
| Download: ML040070165 (51) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Spring City. Tennessee 37381-2000 William R. Lagergren, Jr.
Site Vice President, Watts Bar Nuclear Plant DEC 17 2003 10 CFR 50.55a U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D. C. 20555 Gentlemen:
In the Matter of
)
Docket No.50-390 Tennessee Valley Authority
)
WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 -
AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION -
REQUEST FOR RELIEF 1-RR APPLICATION OF CODE CASE N-597-1, REQUIREMENTS FOR ANALYTICAL EVALUATION OF PIPE WALL THINNING In accordance with 10 CFR 50.55a(a)(3)(i), TVA is requesting relief from specified inservice inspection (ISI) requirements in Section XI of the ASME Boiler and Pressure Vessel Code for WBN Unit 1. Enclosure 1 to this letter provides request for relief 1-RR-05 for NRC review and approval for the use of ASME Code Case N-597-1, "Requirements for Analytical Evaluation of Pipe Wall Thinning,"Section XI, Division 1. The request for relief is an alternative involving the use of the Code Case that has an acceptable level of quality and safety for this application.
Pursuant to the conditions of Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability, ASME Section XI," Division 1, Revision 13, TVA requests review and approval for application of Code Case N-597-1 for the location described.
Code Case N-597-1 is conditionally acceptable for use as described in Table 2 of Regulatory Guide 1.147, Revision 13.
Condition 1 is met as TVA's Flow Accelerated Corrosion (FAC) Program is written to the provisions of EPRI Nuclear Safety Analysis Center Report 2002L-Revision 2.
Condition 2 is met by submittal of this request for relief to use the Code Case.
Condition 3 does not apply to this application of the Code Case as this is a Class 2 component.
U.S. Nuclear Regulatory Commission Page 2 DEC 17 2003 Condition 4 is met by scheduling this component for examination in the Cycle 6 refueling outage.
Condition 5 does not apply to this application of the Code Case as the corrosion phenomenon has been determined to most probably be due to FAC and associated original construction counterbore machining.
No other corrosion phenomenon is suspected at this location. contains details on the evaluation relative to the Code Case for the elbow. contains a copy of the Code Case preceded by the applicable conditions of Regulatory Guide 1.147, Table 2.
TVA requests approval of this relief request for application of Code Case N-597-1 by July 30, 2004, prior to the predicted wall thickness falling below the required minimum wall thickness in September, 2004. contains the commitments in this letter.
If you have any questions about this relief request, please contact P. L. Pace at (423) 365-1824.
Sincerely, W. R. Lagergr n)
Enclosures
- 1.
Request for Relief 1-RR-05
- 2.
Evaluation of Component 103BE252
- 3.
Regulatory Guide 1.147, Table 2 and Code Case N-597-1
- 4.
Commitment List cc:
See page 3
U.S. Nuclear Regulatory Commission Page 3 DEC 17 2003 cc (Enclosures):
NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 Ms. Margaret H. Chernoff, Project Manager U.S. Nuclear Regulatory Commission MS 08G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 SUMPARY:
During implementation of WBN's Unit 1 Cycle 5 Refueling Outage Flow Accelerated Corrosion (FAC)
Program, ultrasonic testing (UT) detected a thin location in an American Society of Mechanical Engineering (ASME) Code Class 2 main feedwater piping elbow at the steam generator Loop 2 inlet nozzle.
A "topography map" of the thin areas was made using UT thickness measurements and the UT data was evaluated both by CHECWORKS and analytical methods. Based on the UT thickness measurements, predicted wear rate, and analytical analysis, it was determined that the predicted wall thickness (tp) will fall below the required minimum wall thickness (tmin) eleven months after startup from the Cycle 5 refueling outage.
However, analysis demonstrates the elbow meets the alternative evaluation criteria of ASME Code Case N-597-1, Section -3600.
This condition was documented on a Problem Evaluation Report in WBN's Corrective Action Program.
The remaining three steam generator elbows to the inlet nozzles were ultrasonically examined and were found acceptable.
The Cycle 5 refueling outage UT of the elbow found the current wall thickness (teas) to be 0.639 inches.
Using an estimated wall thinning rate of 0.025 inches/year (0.0375 inches/18 month cycle)
(plus a ten percent safety factor), the predicted wall thickness tp at the Cycle 6 refueling outage is calculated to be 0.598 inches.
The allowable minimum wall thickness tn as calculated by the equation specified in Code Case N-597-1 Paragraph -3622.1(a)(1) is 0.613 inches.
As noted, the predicted wall thickness tp of 0.598 inches will fall below the allowable minimum wall thickness tmin of 0.613 inches.
The minimum wall thickness is greater than ninety percent of the minimum wall thickness tmn as allowed by the provision of the Code Case.
Thus, TVA is requesting review and approval for application of the Code Case N-597-1 as allowed by the conditions of Regulatory Guide 1.147 Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 13.
Application of the Code Case provides an acceptable level of quality and safety for this application.
Therefore, pursuant to 10 CFR El-i
iI ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 50.55a(a)(3)(i), TVA is requesting approval of this request for relief (1-RR-05) to use the Code Case N-597-1.
1 Main Feedwater System Unit:
System:
Component:
Code Class:
Code Requirement:
Code Requirement For Which Relief is Request:
Basis For Relief:
Proposed Alternative:
FAC Grid 103BE252, 16-inch nominal pipe size feedwater pipe mitered 45 degree elbow at the inlet to Loop 2 Steam Generator Class 2 Piping ASME Section XI, 1989 Edition, IWA-4300 ASME Section XI, 1989 Edition, IWA-4300 provides a process for assessing a component for continued service after a defect has been removed.
This provision stipulates that where the section thickness has been reduced below the minimum design thickness, the component shall be repaired.
As an alternative, the component may be evaluated and accepted in accordance with the design rules of either the Construction Code or Section III.
Regulatory Guide 1.147, Revision 13, conditionally accepted the use of Code Case N-597-1 subject to five conditions.
Some of these conditions require prior NRC review and approval to continue to use the Code Case.
As an alternative to the requirements of IWA-4300, TVA proposes to use the provisions of the ASME Code Case N-597-1 for analytical evaluation of the main feedwater piping, FAC grid 103BE252, subject to the conditions incorporated into the acceptance of the Code Case in Regulatory Guide 1.147, Revision 13.
E1-2
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 Justification For The Granting of Relief:
A copy of the UT data obtained during the Cycle 5 Refueling Outage as printed from CHECWORKS program is shown in Attachment 2 of this enclosure.
The blank locations are either obstructions or where the UT examiner was unable to properly place the transducer due to obstructions in confined access space.
In addition to performing the normal FAC UT for thickness on the grid, a one hundred percent UT scan at the toe of the weld (TOW scan) was performed.
The lowest thickness reading and its location were recorded.
The location of the "Al" (grid origin) is approximately at the top of the horizontal portion of the elbow on the upstream end (end opposite that viewed in Photo 3).
This places Row "E" at the intrados and Row "N" at the extrados.
With the configuration of this portion of the pipe loop, it would be expected that wear would occur in the extrados portion of the subject elbow and would be elongated in the direction of flow.
The UT data evaluator determined the wear for the elbow should be evaluated by the blanket method since the elbow was fabricated from bent pipe which could be expected to cause thickness variations in a circumferential direction.
Also, it was decided bands showing evidence of being countered-bored, (Bands 1, 2, 3, 9, and 10), would not be used to determine the wear of the grid. of this enclosure shows the results of wear determination.
The UT data and the wear data obtained as described above were next entered into a spreadsheet. of this enclosure shows a copy of the data as entered into cells P16 (wear) and cells W16, X16, and Y16 for the UT data.
The wear and the limiting thickness (the lowest UT reading) were used to calculate the remaining service life, (Lrem), shown in cell T16.
The Lrem was calculated to be a time less than the 1.5 years required to operate until Cycle 6 Refueling Outage -
in fact a negative number.
El-3
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 The UT data and the physical configuration of the pipe in question indicates there was an extra long counterbore applied to the upstream end of the elbow during construction and that Band 3 is a transition area between counterbore and non-counterbore.
The thickness required after counterbore is a nominal 0.758 inches with a tolerance of plus 0.005 inches and minus zero inches.
This thickness is only 0.037 inches thicker than the Tcpt value of 0.721 inches.
- Also, during construction the weld was prepared manually on the outside diameter surfaces for nondestructive examination NDE).
As seen in Attachment 1 of this enlosure, the location and orientation of the "thin" areas are not typical of AC wear.
The following additional information is based upon suggested content in an NRC memorandum, dated August 6, 2003, for relief requests where the wall thickness is less than tin.
- 1. Markup of piping isometric showing location where piping is less than tn: of this enclosure shows the location of FAC grid 103BE252 on the main feedwater piping.
The thin areas are located toward the upstream end of the elbow and are shown in Attachment 1 of this enclosure., page EAI-5 shows the thin area of concern.
The grid spacing is a three-inch square.
Photo 1 shows an overall view of the nozzle, the elbow, pipe pup piece, and other elbows, plus pipe restraint devices and a hanger.
Photo 2 shows a close-up looking between the restraint devices which shows a portion of the pipe pup piece, a portion of the subject elbow, and a hanger.
Photo 3 shows a close-up of the subject elbow and the inlet nozzle from the side opposite the view shown in Photos 1 and 2. Each attachment shows the pipe whip restraint devices around the elbow.
E1-4
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05
- 2. Affected System Main Feedwater System
- 3. System normal operating temperature = 440 degrees Fahrenheit (F)
Normal operation pressure = 1145 pounds per square inch (psi)
Design Pressure = 1185 psi
- 4. Pipe size and nominal pipe wall thickness (tnom) :
16-inch Schedule 80 (tnom = 0.844 inches)
- 5.
Code-allowable tin, The allowable minimum wall thickness t as calculated by the equation specified in Code Case N-597-1 paragraph -3622.1(a)(1) is 0.613 inches.
This equation is essentially the same equation for calculating the minimum wall thickness based upon the allowable hoop stresses.
- 6. Current thickness and date measured:
tmea = 0.639 inches measured on September 16, 2003
- 7. Estimated wall thinning wear rate:
0.025 inch/year (0.0375 inch/18 month cycle)
- 8. Predicted wall thickness (tp) at Refueling Outage 6:
0.598 inches.
- 9. Discuss how pressure spikes associated with anticipated system transients are accounted for in establishing tmin-The identified pressure surges due to anticipated system design transients are considered and bounded in establishing tn.
For this piping the Feedwater Check Valve Slam E1-5
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 Transient loadings have also been considered as input.
- 10. Provide licensee's basis for determining the wear thinning rate.
The UT data evaluator determined the wear for the elbow should be evaluated by the blanket method since the elbow was fabricated from bent pipe which could be expected to cause thickness variations in a circumferential direction.
Also, it was decided bands showing evidence of being countered-bored (Bands 1, 2, 3, 9, and
- 10) would not be used to determine the wear of the grid. of this enclosure shows the results of wear determination.
- 11. Provide licensee's criteria for repairing or replacing piping and the basis for the criteria.
TVA's FAC Program allows three options if the predicted remaining service life is less than the amount of time until the next inspection.
These options are:
a) shorten the inspection interval; b) perform a more detailed stress analysis to obtain a more accurate value of the acceptable service life using the evaluation methods specified in TVA's Civil Design Standard, Structural Evaluation of Wall Thinning in Pipe Due to Flow Accelerated Corrosion: and, c) repair or replace the component.
In addition, for piping and components with predicted wall thinning that satisfies the acceptance criteria for continued service, the Program requires monitoring areas containing FAC degradation during successive examinations until repair or replaced with a FAC resistance material and determine the frequency of future examinations by the FAC wear rate or remaining service life calculated from examination data.
E1-6
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 For this application, the current FAC Program requires this elbow to be inspected during the next refueling outage.
The Program requires that when the predicted remaining service life is shorter than the time until the next outage, the appropriate corrective action document be initiated.
A WBN Problem Evaluation Report was initiated during the Cycle 5 refueling outage.
WBN's planned action regarding FAC grid 103BE252, pending approval of this request, is to:
a) continue operation until the Cycle 6 refueling outage; b) during the Cycle 6 refueling outage, ultrasonically examine this elbow to obtain a new set of UT data, obtain a refined wear rate and perform a new analysis; and, c) based on the Cycle 6 data, determine whether to replace the elbow or continue to implement Code Case N-597-1 using the revised (new) analysis.
- 12. Discuss what evaluation methods and criteria the licensee plans to use for performing analytical evaluations of pipe wall thinning in Class 1 carbon steel piping subjected to FAC.
WBN has no Class 1 carbon steel piping within the FAC Program.
- 13. Discuss what evaluation methods and criteria the licensee plans to use for performing analytical evaluations of pipe wall thinning in non-Code Class 1 carbon steel piping subjected to FAC.
Analytical structural evaluation of piping that is subjected to FAC and is within the scope of the WBN ASME Section XI Program is based upon satisfying design basis stress criteria per the Code of Record for the piping (i.e., ASME Class 2 or Class 3).
Specifically, this requires the E1-7
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 determination of the minimum piping component wall thickness that satisfies all pertinent stress requirements including hoop stress due to pressure and longitudinal stress due to pressure and moment loading for all applicable load combinations.
In addition, the minimum required wall thickness to satisfy design basis stress criteria is screened against a limiting thickness of 30 percent of the pipe nominal thickness and the larger value is used to determine remaining life in the component.
This overall approach is summarized in TVA Civil Design Standard DS-C1.2.5, "Structural Evaluation of Wall Thinning in Pipe Due to Flow Accelerated Corrosion" which was developed to provide a consistent evaluation process for determination of a required thickness that satisfies design basis stress criteria and, as such, it provides a rational basis for repair/replacement decisions.
Implementation Schedule:
The alternative to apply Code Case N-597-1 to FAC Grid 103BE252 is requested for the duration of time that the analytical evaluation can support the acceptability of the component or until it is repaired or replaced.
E1-8
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 PHOTO 1 OVERALL VIEW OF MITERED ELBOW WELDED TO STEAM GENERATOR #2 INLET NOZZLE El-9
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 PHOTO 2 VIEW OF PIPE PUP PIECE (LEFT)
AND PORTION OF MITERED ELBOW (RIGHT)
BETWEEN RESTRAINT DEVICES El-10
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 PHOTO 3 VIEW OF MITERED ELBOW VIEWED LOOKING AWAY FROM STEAM GENERATOR NOZZLE El-11 I
II
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 LIST OF ATTACHMENTS UT Data Report CHECKWORKS UT Data Sheet Wear Rate Summary UT and Wear Data Analysis Grid Isometric
ENCLOSURE 1 ATTACHMENT 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT TENNESSEVALX l
DIVIS ~lTRASONIC I
CAMIBRATION REPORT AUTHOM~Y CALIBRATION NO. N PRO1ECT WBN UNIT:
I CALIBRATIONDATE PROC.: I N-UT-26 REVJT.C:21103-01 CALBLOCK NO.: J774 TYPE:
9f39o S s
>ts
'16' INSTRUVMET I TRANSDUCERDATA CAL BLK-TEMP.:
84° 1ERMOMETERS/N:
562779 IXSRUMENT MANUF.:
06-16-04 SERIALNO.:
E36027 DUEDATE:
08-504 COLPLANT:
ULTRAGELII TRANSDItCERMANUF.:
BA BATCRNO.
01225 SERLALNO.:
60VL31j o
SIZE:. 8 4g FREQ.:
- 8.
mhz INSTRUIENT SETINGS CABLE TYPE PIm LENIGTI 72" PROBE:
F THICK CAL.:
iFTI 2PFT
.25Dt~
,)?bRANGE
/,O oD inches A
e
=
=
sVELOCIT:
iJuS I I _ _ _
A GAIN M DUJ M
TCG MODE:
SINGLE O P
DUAL
_L RECTIFY:
POSITIVE I
NEGATIVE 1 T
FULD U
AMLITUDE NORMAL D
SCALE O DISPLAYWIDTH Jo ad inches CALIBRATION TIES INTALCALTNIE:
,230 (1)
VERMCAnONTS F". REFLECTOR a,6 GAIN 72 dB 1)/ 3
- 2) l 3) 4' AMPL /
ETALPATs'd inches
- 5)
- 6)
- 17) 8)
FINAL CAL TNI5 D
(2)
COMPN(S) EXAED TRW REF. EFLECTOR _
A_
GAIN 7C dB
/0; &E2SZ AMPL /00 %
METALPATH.7-0 inhes COMMENTS:
rnAPpl'c FLouw -yq ss T.I.31.21
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.7",;,7d0"
- EXANMOL6, LvL ANI:
SEXAME:
Lvi.
DATE:
RE,Ve
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ENCLOSURE 1 ATTACHMENT 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT
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ENCLOSURE 1 ATTACHMENT 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT 9H 9
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UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT 03 oz 1
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ENCLOSURE 1 ATTACHMENT 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT 03 l)1 A\\
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ENCLOSURE 1 ATTACHMENT 1 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT DATA REPORT E
/
3I 7o'3 E7Ji
-./I. r ElAl-6
ENCLOSURE 1 ATTACHMENT 2 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CHECKWORKS UT DATA SHEET Company Plant Unit DB Nmc
- Tenr.eacee Valley Authority atte Bar
- I
- TVAhB Report ate: 12-DEC-03 Time: 09:36:47 CHECAORPKS FAC Vrainn 1.0r (Piiild 7S)
UT Matri.
J.TNR NAMP
- FW5: Main P oop #2 COMPONENT NAM13 s 103a2s3 OUTAGE AME
- UCS RFO-5 SECTION
- U/S Main Thom - 0.844 (in), Tscreen - 0.721 (in)
VGrid dal 1
3 4
5 6
7 8
9 10 A
0.703 0.780 1.180 B
0.710 0.778 1.092 C
0.737 0.757 0.762 D
0.773 0.762 0.769 E
0.739 0.761 0.772 F
0.744 O.760 0.789 G
0.805 0.757 0.849 R
0.833 0.81 1.142 I
0.786 0.791 1.074 1.205 1.192 1.163 1.034 1.081 1.182 1.221 1.228 1.059 1.040 1.006 0.996 0.979 1.066 0.979 0.972 0.810 0.829 0.815 0.99 0.743 0.'96 0.738 0.'147 1.295 1.267 0.927 O.7V/2 0.772 1.295 0.523 0.987 0.227 0.741 0.780 0.925 1.197 1.170 1.13S 0.951
- o. 183 0.741 1.197 0.456 0.948 0.191 K
0.795 0.766
- 1. C77 1.145 1.096
- 1. C84 0.879
- 0. 869 0.766 1.145 0.379 0.964 0.152 L
0.791 0.714 1.111 1.102 1.114 1.083 1.077 1.067 0.905 0.901 0.714 1.114 0.400 0.987 0.147 M
0.759 0.711 1.119 1.099 1.103 1.081 1.084 1.061 0.944 0.830 0.711 1.119 0.40E 0.979 0.157 N
0.745 0.721 1.122 1.114 1.091
- 1.
89 1.082 1.078 0.957 0.969 0.721 1.122 0.401 0.987
- 0. 155 a
0.742 0.772 1.137 1.135 1.130 1.120 0.972 0.878 0.742 1.137 0.395
- 0. 9PE 0.169 p
0.744 0.737 1.117 1.119 1.127 1.109 0.996 0.89' 0.737 1.127 0.390 0.981 0.168 Q
0.723 0.768 1.119 1.149 1.219 1.179 1.318 0.76 Min 0.703 0.711 0.762 1.099 1.091 1.081 1.077 1.061 0.851 0.V38 Max 0.833 0.816 1.183 1.149 1.114 1.197 1.295 1.267 1.066 0.901 Del 0.130 0.105 0.418 0.050 0.023 0.116 0.218 0.206 0.215 0.163 Ave 0.757 0.761 1.009 1.120 1.103 1.119 1.142 1.145 0.973 0.821 Dev 0.035 0.027 0.157 0.019 0.012 0. es 0.074 0.065 0.059 0.054 Min 0.703 Max 1.205 Del 0.502 Ave 0.956 Dev 0.219 0.710 1.192 0.4S2 0.939 0.192 n.737 1.163 0.426 0.873 0.173 0.762
- 1. 094 0.3 22 0.864 0.140 0.739 1.081 0.342 0.846 0.147 0.744 1.12 0.438 0.890 0.186 0.738 1.221 0.483 0.991 0.183 0.747 1.22S 0.4 81 0.9S6 0.194 0.723 1.219 0.496 1.306 0.194 SECTION SU11MARY Minimum Thickrens Maximum Thickr~eea Delta Average Thickr.ess Standard Deviation -
0.703 1.295 0.592 0.950 0.17' Minimum at l,A Maximum at 7,I ElA2-1
ENCLOSURE 1 ATTACHMENT 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 WEAR RATE
SUMMARY
CMSIy
- T =ze83 Vall-y thorzy Repor:
Dt. a 25-VC-03 Time 13.58:2 F1Zat a h@tti ir m1t t I crHr-kA=
FAC Versloa.oc :3tld 75)
D3 Nama: TIOiSV
- ~
fl au.ry Cogo&ent
- 103S252 LiI.
F52 Hai. FI Locp 2 C-cm-try riPe S
45-DIl EOTW t-ction:
U/S Hal Scn -
0.34 In), Tinit -
0.000 (in), Tcreen -
0.721 (1.,
parocls)
Grld Sl.
14o. of Avg.
Standard Kil.
- k.
H.x. Thk.
Total u..r Total Svr.
(RXC)
Pollts T.k.
DLv.
IRxCI C5XC; Life Was:
aIthod Hours.
UIOC5 R3a-S l0x17 125 C.95C 0.171 C.701:: A:
1.29;t7 0.1,:
l-----
65472.C ElA3-1
ENCLOSURE 1 ATTACHMUENT 4 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT AND WEAR DATA ANALYSIS I
C I
D E
F G
H l
I J
I K
I L
I M
I N
0 P
I Q
I R
I S
I T
1 The below FAC grid UT data has been reviewed. evaluated for adeqluacy, compared to the acceptance criteria, and are acceptable for continued service. These grids may be reinsulated 2
and returned to service.
3 Original signed by Evaluator Original signed by Verifier 4
Evaluata pmn4
.fbal. adle. NEAJ.tN VW91 fXef Ipfi.
4ae). Nt-UAN 5
Definitions:
6 LOC' = for Tees, Reducers. and Expanders, U-Upstream Main Run. D=Downstream Main Run. B=Branch, L=Large diameter end, and S=Smal diameter end.
7 Taccpt-Acceptable Minimum Thickness, calculated value unless indicated. fllm=RFO-5 minimum measured thickness. Wmeas=Wear, measured, fram CHECWORKS. Lremwpredicted Life 8
remaining-(Tlim-Taccpt)f(WRcorr SF). WRcorr=Wrmeas x (greater of WR current/Wravg or 1). Repair or Replaco?=Lrem>1.5. Expand Sample?=Tflmo-(0.5Tnom) and (Lrem'3.0).
9 10 WO No.: 02-012720-000 12 O
1.0 0.875 0.5 Ltime Tamcpt WRcurrent WRavg WRcurrent Rcorr T..
Wmeas WRmeas Repair or Expand.
I-13 C
.....1.............
(years)
(inch)
(in0 (inyr) lVVRavg)
Ci.
. (inch) finlyr)
Replace? Sample?
Lrem, yrs 14 Loop 2 Inside Crane Wall - Class B 15 5-075 103BP251 0.844 0.739 OA22 7.52 0.613 26.957 30.440 0.886 0.018 0 137 0.018 NO NO -;
4,-
16 5-076 103BE252 0.844 0.739 0.422 7.52 0.721 29.485 33.294 0.886 0.025 YES YES 2.0) 17 5-077 1038N253 0.844 0.739 0.422 7.52 0.490 33.697 38.050 0.886 00100 0.013 No NO 16.5 1 8 Comments:
19 U/S T.O.W Scan value on 103BE252 is from mapped/scanned area. U/S end of elbow, and weld to P251, are covered by support.
20 U/S T.O.W Scan value on 103BP251 is from T.O.W scan around weldolet. D/S end of pipe, and weld to E252, are covered by clamp..
21 See PERs 03-016397-000 (specific) and 03-016393-000 (generic). One local spot (see map) shows a small area with 0.639" thickness, 22 Further evaluation by Civil Engineering has determined 103BE252 is acceptable for continued service for 11 months and will be dispositioned 23 in accordance with corrective actions of PER 03-016397-000.
24 25 M16 = IF(OR(K16=-,LlG="').-NA-.(K16/L16))
T16 = IF(OR(O1 6="NA"N 1 6="NA"),'NA,(01 6-JI 6)/(NI 6'1. 1))
26 N16 = IF(Q16="NA","NA".(MAX(1,M16)yQ16))
V16 = Input 27 016 = IF(MIN(W16:Y16)>0,MIN(WI6:Yi6),"NA' t)
W16 = Input 28 P16= Input X16= Input 29 Q16 = IF(P16="NA",-NA",P16/116)
Y16 = Input 30 R16 = IF((T16>1.5),"NO","YES')
Z16 = 0.3F16 31 S1 = IF(AND(T1 6>3, 01 6>H1 6),"NO","YES")
AA1 6= IF(J1 6='"',"',IF(Zl 6>J1 6+0.0005,"Error,"OK"))
ElA4-1
ENCLOSURE 1 ATTACHMENT 4 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 UT AND WEAR DATA ANALYSIS C
D E
V W
X Y
Z AA 1
The below FAC grid UT data has 2
and returned to service.
Not*~pnti'd rt.t.
3 4
5 Dofnnltons:
cW Ctal:-T-minT Measured 6
LOC' = for Tees. Reducers. and Evel US
.d DS:4.:
7 Toccpt=Acceptable Minimum T h11th.odi'>-,.i'wf., '..'
8 rernaining=(Tlim-Taccpt)(W Toe Grid Toe Oi 0.3 BAnd o
of Tnorn 1 FIL Grid Numb r L
WTmin 12
~~~0 Pon~
nh ic nhCheck 14 Loop 2 Insid Cr 15 5-075 103BP251 BA 0.763 0.707 OK 16 5-076 103BE252
=
BL 639 1
3
.77...
OK 17 5-077 103BN253
.BA.
0*731 0.744 OK 18 Comments:
19 UIS T.O.W San 20 UIS T.O.W San 21 See PERS03-016 22 FUrther evaluation 23 in acordance wit 24 25 26=
28 29 30 3 1 E1A4-2
ENCLOSURE 1 ATTACHMENT 5
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 GRID ISOMETRIC
ENCLOSURE 2 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 EVALUATION OF WBN FLOW ACCELERATED CORROSION (FAC) PROGRAM COMPONENT 103BE252 RELATIVE TO ASME CODE CASE N-597-1 Background and Objective:
This evaluation addresses flow accelerated corrosion (FAC) induced wall thinning for WBN FAC Component 103BE252, an American Society of Mechanical Engineers (ASME)Section III, Class 2, 16-inch Schedule 80 (i.e., Nomial thickness (tnom) =
0.844 inches), elbow located in Loop 2 of the Unit 1 Main Feedwater System.
This elbow is fabricated from SA-333 GR 6 material.
Design pressure and temperature are 1185 pounds per square inch (psi) and 600 degrees Fahrenheit (F),
respectively.
Based on wall thickness data taken during the Cycle 5 refueling outage in September 2003 (i.e., 0.639 inches minimum measured remaining thickness) and wear rates computed using WBN FAC Program methods (including ten percent safety factor), the minimum projected wall thickness (tp) at the time of Refueling Outage-6 (i.e., 1.5 years after Refueling Outage-5) was determined to be 0.598 inches.
This evaluation provides technical justification that tp satisfies ASME Code Case N-597-1 requirements.
Each pertinent section of the code case is addressed separately below:
Section -3500 -
Wall Thickness Acceptance Standards:
Per Section -3500 (a)(1), the acceptance standard that tp (0.598 inches) must be greater than 0.875 tom = 0.739 inches is not satisfied for this component.
However, tp is significantly greater than the limiting thickness requirement specified in Section -3500(d) for ASME Class 2 components (i.e., tp = 0.598 inches > 0.2 t
= 0.169 inches).
Thus, further evaluation is performed in accordance with Section -3600, "Analytical Evaluation for Class 2 and Class 3 Piping Items,O as permitted by Section -
3223, "Acceptance by Engineering Evaluation."
E2-1
ENCLOSURE 2 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 Section -3600 -
Analytical Evaluation for Class 2 and Class 3 Piping Items Section -3621 -
Evaluation of Pipe, Elbows, Branch Connections and Reducers:
Per Section -3621(d), the ratio, R/tp = 8.0 inches/0.598 inches = 13.4, is less than 50.
Thus, the potential for buckling requires no further evaluation.
Section -3622 -
Thickness Evaluation:
In determining acceptance in accordance with Section -3622, the wall thickness data taken during Refueling Outage-5 is used with the wear rate (plus a ten percent safety factor) applied for the length of service expected (i.e., 1.5 years until Refueling Outage-6) to determine projected thickness.
For WBN FAC component 103BE252, a minimum projected wall thickness value (tp) of 0.598 inches has been computed for Refueling Outage-6.
Considering the design pressure (P =
1185 psi) and allowable stress for the elbow material (S =
15000 psi @ 600 degrees F), the equation from the construction code is used to determine the required thickness (tan) as follows:
t
=
P Do
=
1185 psi (16.00in) 0 613in nun 2 (S + y P) 2 [15000 psi +0.4(1185 psi)]
For acceptability, Section -3622.1(a) specifies that tp may not be less than ninety percent of tin.
to, 0.598 in = 0.976 > 0.900 t-n 0.613in Since the ninety percent tin criteria is satisfied, the requirements of Section -3622 are satisfied without further evaluation.
Section -3623 -
Piping Stress Evaluation:
The effect of the pipe longitudinal pressure and bending stresses was evaluated for WBN FAC Component 103BE252 using a detailed stress analysis in accordance with the Construction Code of Record and the requirements of Section
-3623.
This detailed stress analysis used as input the E2-2
ENCLOSURE 2 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 Refueling Outage-5 measured thickness data for cross section in question including the wear rate (plus a ten percent safety factor) applied for the length of service expected (i.e., 1.5 years until Refueling Outage-6).
The stress analysis methodology applied accounted for reduced section properties and induced bending due to neutral axis offset considering the projected thicknesses at the time of Refueling Outage-6.
Also, the stress evaluation accounted for the impact on the elbow stress intensification factor (Section -3623.4) due to the projected wall thickness at Refueling Outage-6 and the intensification factor was increased accordingly.
Pipe bending loads were taken from the analysis of record which is a rigorous static and dynamic qualification of the piping that demonstrates satisfaction of ASME Class 2 requirements.
Although, the analysis of record assumes nominal thickness for all piping components, the 1.143 stress allowable factor permitted in Section -3623.1 was not used in the structural evaluation.
This stress evaluation showed that the applicable Code of Record ASME Section III, Class 2 equations remain within required allowable stresses when considering the reduced thickness profile of the affected cross section as projected to Refueling Outage-6.
Specifically the maximum primary and primary plus secondary stress ratios (applied/allowable) were found to be 0.917 and 0.865, respectively.
Thus, the requirements of Section -3623 are satisfied.
Section -3624 -
Evaluation of Branch Connections:
The location of FAC Component 103BE252 is a piping elbow and not a branch connection, therefore, the requirements of Section -3624 are not applicable.
Section -3625 -
Evaluation for Cyclic Operation:
This component was evaluated for cyclic operation using Section -3625(b).
For the WBN main feedwater system, review of the stress range reduction factors of Table 3625-1 indicates that a factor of 1.0 would be applicable since the applicable number of full temperature thermal cycles for one operation cycle is much less than the 650.
In addition, projected thicknesses at Refueling Outage-6 have been included in the development of the stress intensification factor for the Section -3623 analysis discussed above which demonstrated satisfaction of pertinent stress equations and hence, suitability for cyclic service in accordance with ASME Class 2 piping requirements.
For Section -3625(c),
E2-3
ENCLOSURE 2 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 evaluation of ASME Section III, NC-3600, Equation 11 (i.e.,
sustained primary plus thermal expansion stress) indicates that the revised stress ratio (i.e., applied/allowable) remains less than 1.0 for the analysis performed in the Section -3623 evaluation. This ensures that the local overstrain in the thinned region for the combination of maximum sustained plus thermal expansion stresses have been adequately considered.
Thus, the requirements of Section -
3625 are satisfied.
==
Conclusion:==
As discussed above, the pertinent elements of the Code Case N-597-1 evaluation have been applied to address the projected thickness of WBN FAC Component 103BE252 at the time of Refueling Outage-6.
For each element, acceptability has been demonstrated in accordance with N-597-1 requirements.
Thus, it is concluded that this piping component is acceptable for service without repair or replacement until the WBN Unit 1 Cycle 6 refueling outage.
E2-4
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 REGULATORY GUIDE 1.147 TABLE 2 AND APPLICABLE TO AND COPY OF ASME CODE CASE N-597-1
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 REGULATORY GUIDE 1.147 TABLE 2 CODE TABLE 2, CONDITIONALLY ACCEPTABLE SUPPLEMENT/
CASE SECTION XI CODE CASES EDITION NUMBER CONDITION.
N-586 Alternative Additional Examination Requirements for Class, 2, 5/98E and 3 Piping, Components, and Supports, Section Xl, Division 1 The engineering evaluations addressed under Item (a) and the additional examinations addressed under Item (b) shall be performed during this outage. If the additional examinations performed under Item (b) reveal indications exceeding the applicable'acceptance criteria of Section XI, the engineering evaluations and the examinations shall be further extended to included additional evaluations and examinations at this outage.
N-593 Alternative Examination Requirements for Steam Generator 11/98E Nozzle to Vessel Welds, Section Xl, Division Essentially 100 percent (not less than 90 percent) of thee.
examination volume A-B-C-D-E-F-G-H must be nspected.
N-597-1 Requirements for Analytical Evaluation of Pipe Wall Thinning, 2/01 E Section Xl, tDivision I (1) Code Case must be supplemented by the provisions of EPRI Nuclear Safety Analysis Center Report 202L-R2. April 1999,
'Recommendations for an Effective Flow Accelerated Corrosion Program,' for developing the Inspection requirements, the*
method of predicting the rate of wall thickness loss; and the value of the predicted remaining wall thickness. As used in NSAC-202L-R2, the terms should' and shall" have the same expectation of being completed.
(2) Components affected by flow-accelerated corrosion to which this Code Case are applied must be repaired or replaced in accordance with the construction code of record and Owner's requirements or a later NRC approved edition of Section III of the ASME Code prior to the value of t reaching the allowable minimum vall thickness, t,,, as specified In -3622.1 (a)(1) of this Code Case. Alternatively, use of the Code Case is subject to NRC review and approval.
(3) For Class 1 piping not meeting he criteria of -3221, the use of evaluation methods and criteria Is subject to NRC review and approval.
(4) For those components that do not require immediate repair or replacement, the rate of wall thickness loss is to be used to determine a suitable inspection frequency so that repair or replacement occurs prior to reaching allowable minimum wall I___________
thickness, t,.
E3-1
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 REGULATORY GUIDE 1.147 TABLE 2
. CODE TABLE 2, CONDITIONALLY ACCEPTABLE 3UPPLEMENTI CASE SECTION XI CODE CASES EDITION
.NUMBER CONDITION N-597-1 Requirements for Analytical Evaluation of Pipe Wall Thinning, 2/01 E (continued)
Section Xl, Division 1 (5) For corrosion phenomenon other than flow accelerated corrosion, use of the Code Case is subject to NRC review and approval. Inspection plans and wall thinning rates may be difficult to justify for certain degradation mechanisms such as MIC and pitting.
N-599 Alternatives to Qualification of Nondestructive Examination 2198E Personnel for Inservice Inspection of Metal (Class MC) and Concrete (Class CC) Containments, Section Xl, Division This Code Case may not be used when a licensee updates to the 1992 or later Edition of Section XI that requires the use of ANSI/ASNT CP-189, "Standard for Qualification and Certification of Nondestructive Testing Personnel."
N-606-1 Similar and Dissimilar Metal Welding Using Ambient 6/98E Temperature Machine GTAW Temper Bead Technique for BWR CRD Housing/Stub Tube Repairs, Section Xl, Division 1 Prior to welding, an examination or verification must be performed to ensure proper preparation of the base metal, and that the surface is properly contoured so that an acceptable weld can be produced. The surfaces to be welded, and surfaces adjacent to the weld, are to be free from contaminants, such as, rust, moisture, grease, and other foreign material or any other condition that would prevent proper welding and adversely affect the quality or strength of the weld. This verification is to be required in the welding procedures.
N-616 Alternative Requirements for VT-2 Wsual Examination of 6/98E Classes 1, 2, 3 Insulated Pressure Retaining Bolted Connections,Section XI, Division 1 (1) Insulation must be removed for VT-2 examination during the system pressure test-for any 17-4 PH stainless steel of 410 stainless steel stud or bolt aged at a temperature below 1 1000F or with hardness above R. 30.
(2) For A-286 stainless steel studs or bolts, the preload must be verified to be below 100 Ksl or the thermal insulation must be removed and the Joint visually examined.
(3) For nuts conforming to SA-194; removal of the insulation for visual Inspection is not necessary.
(4) Prior to conducting the VT-2 examination, the provisions of IWA-5213, "Test Condition HoldingTim-es." 1989 Edition, are to be followed.
E3-2
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE N-597-1 CASES OF ASMIE BOILER AND PRESSURE VESSEL CODE Approval Date: September 7, 2001 See Numeric Index for expiration and any reaffirmation dates.
Case N-597-1 Requirements for Analytical Evaluation of Pipe Wal Thinning Section XI, Division 1 Inquiry: What requirements may be used for analyti-cal evaluation of Classes 1, 2 and 3 piping items subjected to internal or external wall thinning?
Reply: It is the opinion of the Coirnittee that the following rules may be used.
-1000 SCOPE This Subsection provides requirements for analytical evaluation of Classes 1, 2, and 3 piping items (e.g.,
piping and fittings) with internal or external wall thin-ning. These requirements are applicable to nonplanar flaws.
value, tp, may be used in determining acceptability for continued service. Methods of predicting the rate of wall thickness loss and the value of :, shall be the responsibility of the Owner.
.3220 Acceptance
-3221 Acceptance By Examination Piping items whose examination and evaluation re-sults reveal that t, meets the acceptance standards of
-3500 or the Construction Code are acceptable for continued service. When these criteria are not met, the alternatives of -3222, -3223, and -3224 may be used.
Fig. -3220-1 shows a flow chart of the acceptance alternatives.
-3222 Acceptance by Repair/Replacement Activity Piping items whose thickness is less than that required by -3500. -3223, -3224 shall be corrected by a repair/
replacement activity.
.3223 Acceptance by Engineering Evaluation Piping items whose examination and evaluation re-sults reveal that the criteria of -3221 are not satisfied may be accepted for continued service by engineering evaluation.
(a) For Class I piping items, this evaluation shall be conducted in accordance with evaluation methods and criteria developed by the Owner.
(b) For Classes 2 and 3 piping items, an acceptable evaluation method and criteria are provided in -3600.
Alternative evaluation methods and criteria may be specified by the Owner.
.3224 Acceptance by Reduction of Time to Next Examination Piping items whose examination and evaluation re-sults reveal that the criteria of -3221 are not satisfied, are acceptable for continued service when the time to the next examination for the affected piping items is reduced such that the acceptance criteria of -3221 or
-3223 are met using the tp for the reduced examination period.
-3000 ACCEPTABLE STANDARDS
-3100 Preservice Examination Piping items examined prior to commercial service are acceptable for service when the measured wall thickness meets the requirements of the Construction Code.
-3200 Inservlce Examination
-3210 General Upon completion of pipe wall thickness examinations, the predicted remaining wall thickness, tr, at the time of the next scheduled examination shall be calculated for piping items under evaluation. The predicted re-maining wall thickness Is the spatial distribution of wall thickness remaining throughout the piping item and may have a unique value at any given location on the piping item. Alternatively, the minimum predicted 985 SUPP. 2 - NC E3-3
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597-1 CASES OF ASME DOILER AND PRESSURE VESSEL CODE FIG. -3220.1 ACCEPTANCE FLOW CHART SUPP. 2 - NC 986 E3-4
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOILER AND PRESSURE VESSEL CODE Required Thickness Piping item Reference Straight pipe
-3600(al(1)
Elbows
-3500tsl(1)
Reducer3
-2500(al(21 Tease
-3500n)13)
Branch
-3500(a113) connections1 Designed Item
-3500(a114)
Other items
-3GOO(bl 1Altemate of -3600Cal) may be used.
Thickness Limit Code class Reference I
-3=O.(cl 2
-3500(d) 3
_3500(C)2 2Atemate criteria may be developed In accordance with -3500(M).
FIG..3500-1 WALLTHICKNESSACCEPTANCESTANDARDFLOW CHART
-3500 WaU Thickness Acceptance Standards A flow chart for the acceptance standards is shown in Fig. -3500-1.
(a) A Class 1, 2, or 3 butt welded pipe, elbow, branch connection, or reducer piping item is acceptable for continued service without further evaluation when tp at all locations on the piping item meets the following requirements.
(1) For straight pipe and elbows purchased to a nominal pipe specification with an allowable wall thick-ness undertolerance of 12.5%, t shall be not less than 0.875,,,, except that, for Class I short radius elbows, an evaluation shall be conducted to show that the requirements of N-3642.2 are net.
(2) For the small end of concentric and eccentric reducers. r, shall be not less than 0.875 for the pipe size at the small end. For the large end, the large end transition and the conical portion, t, ihall not be less than 0.875 tl for the pipe size at the large end.
For the small end transition, the required thickness shall be gradually reduced from that required at the large end to that required at the small end (see Fig.
.3622-1).
(3) For tees and branch connections, r, shall be not less than 0.875 t.,3 for the same size pipe for regions outside the limits of reinforcement required by the Construction Code used in the evaluation. For regions within the limits of reinforcement, t, shall be 917 E3-5
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOILER AND PRESSURE VESSEL CODE not less than the thickness required to meet the branch reinforcement requirements of the Construction Code.
(4) For regions of piping items designed to specific wall thickness requirements, including designed weld counterbores and regions with integral reinforcement, 4r shall be not less than the minimum design thickness, including tolerances and excluding any corrosion allow-ances. specified in the original design analysis for the piping item.
(5) As an alternative to the requirements of
-3500(a)(2) and -3500(a)(3), for reducers, tees, or branch connections purchased to fitting standards allowed in Table NB-3132-1 and for which baseline as-installed thickness measurements exist. r, shall not be less than 0.875 times the as-installed thickness measurements, except that the thickness shall not be less than 0.875 tnCl-(b) Acceptance criteria for Class 1 2, and 3 pumps.
valves, flanges, reducing elbows. socket weld fittings, and any other piping items not covered by -3500(a) shall be the responsibility of the Owner.
(c) For any Class I piping item, when 4, at any location is less than 0.3 t.o. further evaluation is beyond the scope of this Case.
(d) For any Class 2 piping item, when t, at any location is less than 0.2 :,,,,
further evaluation is beyond the scope of this Case.
(e) Except as provided in (1 below, for any Class 3 piping item, when t4 at any location is less than 0.2 t,,, or 0.5 :,.,, whichever is less, further evaluation is beyond the scope of this Case. Lee value of t-,
shall be determined in accordance with -3600.
(19 As an alternative to -3500(e), decreased wall thickness. including local through-wall leakage in Class 3 piping items whose maximum operating temperature does not exceed 200'F and whose maximum operating pressure does not exceed 275 psi may be accepted.
Evaluation methods and acceptance criteria shall be specified by the Owner.
(b) Analytical evaluations shall be conducted using the predicted wall thickness, t4, at the next examination of the piping item. The methods used to determine rp are the responsibility of the Owner.
(c) A piping item is acceptable for continued service if the minimum pipe wall thickness, branch reinforce-
- ment requirements, and piping stress criteria of the Construction Code used in the evaluation are met for all specified loading conditions.
(d) As an alternative to -3610(c), butt welded pipe, elbow, branch connection, and reducer piping items may be evaluated in accordance with -3620.
(e) Alternative evaluation of pumps, valves, flanges, and other piping Items are the responsibility of the Owner.
(t) Piping items under evaluation with r,, exceeding the acceptance standards of -3500 and satisfying -3600 shall be monitored for continued degradation. The fre-quency and means of monitoring for degradation are the responsibility of the Owner.
-3620 Evaluation of Pipe, Elbows, Branch Connections, and Reducers
-3621 General Requirements (a) The evaluation shall meet he requirements of
-3622 and -3623.
(b) For a branch connection or tee, the region within the limits of reinforcement defined in the Construction Code shall meet the requirements of -3624.
(c) Evaluations shall be conducted using the appro.
priate piping equations, loadings, load combinations, allowable material properties, and other acceptance standards from the Construction Code used in the evaluation, except as specifically modified by this Case.
(d) When the ratio R, is greater than 50, the potential for buckling of the thinned region shall be evaluated. Evaluation methods and acceptance criteria shall be specified by the Owner.
-3600 Analytical Evaluation for Class 2 and Class 3 Piping Items
-3610 General Requirements (a) Analytical evaluations shall be conducted in ac-cordance with Construction Code. Later Code Editions and Addenda may be used. Use of later Code Editions and Addenda shall be reviewed for acceptability to the regulatory and enforcement authorities having jurisdic-tion at the plant site.
-3622 Thickness Evaluation
-3622.1 Evaluation for Minimum Wall Thickness (a) Except as provided in -3622.1(b), the value of rp at any location shall not be less than 90% of e
minimum wall thickness of the piping item, rj, required for design pressure, defined in the Construction Code used in the evaluation, exclusive of any additional corrosion allowance.
E3-6
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597-1 CASES OF ASME BOILER AND PRESSURE VESSEL CODE (1) For straight pipe, bends, and elbows, tin shall be determined by:
PD.
2(S + yP)
(2) For concentric and eccentric reducers.
in at each end shall be equal to tj, of straight pipe of the same nominal size as the reducer end. For the conical portion of the reducer and the transition at the large diameter end, :,,.. shall be that of the large diameter end. A gradual transition in t n shall be assumed for the transition at the small end (see Fig. 3622-1).
(3) For branch connections and tees, except at regions providing reinforcement of the opening required by the Construction Code used in the evaluation, ta shall be as-required for straight pipe.
(b) When t, is less than 0.9 ti,,i at any location, additional evaluations may be conducted to determine the allowable local thickness, tce subject to the limita-tions in (c). The thinned region and the parameters that define the depth and extent of thinning are illustrated in Fig. -3622-2. The allowable local thickness shall be determined in accordance with any one of the methods in -3622.2, -3622.3, -3622.4. -3622.5, or -3622.6.
(c) Local thinning evaluation shall not be allowed for the following:
(I) A region adjacent to any branch connection on the run piping, unless the distance between the center of the branch connection and the edge of the thinned area predicted to be less than tn exceeds Ds, where D is the nominal inside diameter of the branch connection and L, is the maximum dimension of the thinned region less than t ;n.
(2) At the small end transition of a reducer.
(3) Inner portion of elbows and pipe bends (Fig.
-3622-3), excluding a region within I1.
,t,;
of the butt welds, unless the rin m in the evaluation of
-3622.2, -3622.3, or -3622.4 Is replaced by i',n. de-fined by:
i'At (0-5 +I +
cos,)
s
-3622.2 Local Thinning-Limited Transvcrsc Extent (a) The evaluation procedure shall consider the depth and extent of the affected area and require that the wall thickness exceed r,
, for a distance that is the greater of 25 jRacmr,,mor 2Lm,, between adjacent thinned regions, where Rnm is the mean radius of the piping item based on nominal wall thickness and "g is the average of the extent of L,, below,,, for the adjacent areas (see Fg. -36224). Alternatively, the adjacent thinned regions shall be considered a single thinned region in the evaluation.
I (b) Provided that the transverse extent of wall thin-ning predicted to be less than t,..,
is less than or equal tojR
, the allowable local thickness, hav, shall be determined from Table -3622-1, wbere Rmi.
is the mean radius of the piping item based on the minimum wall thickness r". For straight pipe, Table
-3622-1 may be used when L,) exceeds JR_;;; i;,
except that an additional thickness tb shall be added to the value determined from Table -3622-1.
(c) This approach shall not be used to evaluate a reducer.
-3622.3 Local Thinning-Limited Axial and Transverse Extent (a) When the maximum extent of wall thinning, 4,,
for which thickness is predicted to be less than tr, is less than or equal to 2.655/=,,i n,,, and t is greater than 1.13 t,.
td, shall be determined by satisfying (b) below and (c) or (d) below. This approach requires that adequate reinforcement be available surrounding the thinned area in accordance with (c) or (d). This evaluation approach is not applicable for the following conditions:
(I) Thinned areas adjacent to branch connections, when. the reinforcement zone for the thinned area would overlap the required reinforcement of the branch connection.
(2) Thinned areas for which any portion of the reinforcement zone would lie on the conical or small diameter transition zone of a reducer.
(3) Adjacent thinned areas qualified by this ap-proach when the reinforcement zones associated with each area would overlap.
(b) The thickness of the remaining pipe wall at the thinned section is adequate if the following equation is satisfied.
0.3534 (c) If there is a surrounding reinforcement zone with predicted thickness of at least tmn for a minimum 989 SUPP. 2 - NC E3-7
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597-1 CASES OF ASME BOILER AND PRESSURE *VESSEL CODE dimension of L/2 in all directions, reinforcement for the thinned area shall satisfy the following equation.
tmi. I Cosa to.
F L
) (t-'-)
(d) As an alternative to (c), the reinforcement adjacent to the thinned area shall justify the following equation.
t.- 'a I (0.935A;n Fan L,.j,,
.3622.4 Local Thinning-Unlimited Transverse Extent (a) The evaluation shall include consideration of the depth and extent of the affected area less than m.m*
The wall thickness shall exceed rn for an axial distance the greater of 25 Rrntom or 2 L between adjacent thinned regions at each circumferential location on the piping item (see Fig. -3622-5). Alternatively.
the adjacent thinned regions shall be considered a single thinned region in the evaluation.
(b) Thickness 'do: shall be determined from Table
-3622-1.
(c) This approach shall not be used to evaluate a reducer.
.3622.5 Local Thinning-Elbows and Bent Pipe (a) For locations farther thanRmjinmoj from welds to adjacent piping items, the predicted thickness on the outer portion of an elbow or bend may be less than
- j. for straight pipe. The local allowable thickness at each location shall be deternined by:
hM 2 0.5 +
0.5 tS~ft I + cose Rb(Z) where RbM/R.~= ratio of elbow bend radius to mean pipe radius, based on tr,,,, for the same size pipe
-3622.6 Local Thinning-Central Portions of Concentric Reducers (a) For the conical portion of concentric reducers, the loc allowable thickness less than rmiD shall satisfy the following equation:
SUPP.2 - NC (b) For the flared transition at the small end of a concentric reducer, the local allowable thickness shall be gradually reduced from the value determined at the conical end of the flare to td. for the small end of the reducer.
(c) ibis approach shall not be used to evaluate eccentric reducers.
-3623 Piping Stress Evaluation
.3623.1 Evaluation Requirements (a) The effects of piping stresses shall be evaluated in accordance with the equations of the Construction Code used in the evaluation. If the piping design analysis is based on nominal piping thickness, the allowable stresses used in a stress analysis based on predicted thickness, r, (see -3210), may be multiplied by 1.143. Consideration shall be given to changes in the pipe metal area, pipe inside area, section modulus, and stress indices or stress intensification factors, as described in -3623.2, -3623.3 and -3623.4. The effects of cyclic operating conditions shall be addressed in accordance with -3625.
(b) The piping stress evaluation, shall be based on the predicted thickness at. each cross section of the piping item that exhibits significant thinning or is affected by a change in stress index or stress intensifica-tion factor. Alternatively, the evaluation may be based on the limiting cross section.
-3623.2 Nominal Longitudinal Pressure Stresses (a) The pipe metal area and the pipe inside area, for the thinned cross section might result in stresses different from those of the piping stress analysis of record.
(b) For simplified analysis, the piping item may be assumed to be uniformly thinned with a thickness of For this approach, the nominal longitudinal pres-sure stress shall be determined by:
SoPD.
P41.,Wn, When evaluating reducers, the large and small ends shall be evaluated separately. For the large end, tpmni shall be determined from all locations for the large end and conical section. For the small end, !,,,
for the entire reducer shall be used.
990 E3-8
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASMtE JOI ED AND PRESSURE VESSEL CODE (c) Detailed stress analysis may be conducted based on the complete set of measurements around the thinned cross-section of the piping item. The nominal longitudi-nal pressure stress, S, shall be determined by:
PA; Ap, (1) To evaluate piping at a branch connection beyond the limits of reinforcement, it shall be assumed that the entire region within limits of reinforcement Is at thickness tin for the unreinforced pipe section, with the outside surface at the pipe nominal outside radius.
If excess reinforcement is available within the limits of reinforcement, the excess metal area may be included in A.,.
(2) When evaluating the longitudinal pressure stress in the central cone of a reducer, the stress shall be determined based on the local radius at the cross section and the local t, at and adjacent to the cross section of interest, except that the resulting stress shall be multiplied by a factor of I/cosa.
(d) Vben using Code Editions and Addenda that require use of stress indices, the nominal longitudinal stress determined in accordance with (b) and (c) shall be doubled.
-3623.3 Nominal Longitudinal Bending Stresses (a) Thinning of the piping item cross-sectional area might result in bending stresses different from those of the piping stress analysis of record. The nominal longitudinal bending stress, Sb, for the various loading conditions and load combinations shall be deter-mined by:
iAli + PAss s2 a,
(c) Detailed stress analysis may be conducted based on a complete set of measurements around the thinned cross section of the piping item.
(d) When evaluating thinning at the cross section of a branch connection, the requirements of -3623.2(c)(1) shall be meL
-3623.4 Stress Intensification Factors and Stress Indices The local piping item wall thickness could affect the stress indices or stress intensification factors used in determination of the effective piping stress at a branch connection. When reduced wall thickness could increase these factors, the effect shall be considered by using a reduced piping item thickness detennined in accordance with (a), (b), or (c).
(a) Except as allowed in b) or (c), stress intensifica-tion factors or stress indices for a piping item shall be based on the assumption of uniform wall thickness, using a value of t,,,
and an associated mean pipe radius in the formula for these factors.
(b) As an alternative (a) above, the factors may be based on the average t, of the piping item excluding branch reinforcement zones, except that predicted thick-ness at locations within a distance of twice the pipe nominal all thickness from butt welds to adjacent components need not be considered. For reducers, the average :,, of the small end shall be used with the small end diameter to determine the factor.
(c) As an alternative to (a) or (b) above, stress analysis of thinned piping items may be conducted to show the effects of wall thinning and the distribution of stresses on an affected piping item.
-3624 Evaluation of Branch Connections
-3624.1 The region of branch connections and tees within limits of reinforcement of the Construction Code used in the evaluation shall be evaluated in accordance with -3624.2 or -3624.3.
-3624.2 Branch Connections Not Requiring Reinforcement (a) The region on the piping run shall be evaluated in accordance with the requirements of -3622 and -3623, without consideration of the branch connection, except that tr, within a region of radius of Di of the branch pipe from the center of the branch connection shall not be less than rj. for the pipe run.
(b) The branch piping shall be evaluated in accord-ance with the requirements of -3622 and -3623.
(b) For simplified analysis, the piping item section modulus may be based on a uniformly thinned section with thickness t When evaluating reducers, the large and small ends shall be evaluated separately. For the large end, r,,, shall be determined from all locations for the large end and conical section. For the small end,,,,,,
for the entire reducer shall b used.
991 E3-9
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOILER AND PRESSURE VESSEL CODE
-36243 Branch Connections Requiring Reinforcement (a) Branch reinforcement requirements shall be deter-mined in accordance with the Construction Code used in the evaluation.
(b) For the region of the piping run that provides branch reinforcement, the value of t, at any location shall not be less than t, for the nominal pipe run plus any required reinforcement at that location.
(c) For the region of the branch pipe that provides branch reinforcement, t shall not be less than tsu for the branch pipe plus any required reinforcement
.3625 Evaluation for Cyclic Operation (a) For piping items with t not less than 0.75 tw and subject to no more than 150 equivalent full temperature cycles at the time of the next examination.
in accordance with the Construction Code used in the evaluation,piping stress equations that include thermal expansion and anchor movement stresses need not be evaluated.
(b) For piping items not meeting the requirements of -3625(a), when the design includes consideration of thermal expansion stresses, the allowable stress range for expansion stress shall be determined in accordance with the Construction Code used in the evaluation, except that the stress intensification factor, 1. shall be revised to take into account the geometry of the thinned region. As an alternative to establishing a revised stress Intensification factor, the stress range reduction factors of Table -3625-1. which are based on an increase in the stress intensification factor by a factor of 2 over the life of the component, may be'used.
(c) The potential for local overstrain in the thinned region for the combination of maximum sustained plus thermal expansion stresses shall be considered. Sus-tained loads include pressure, weight, and other sus-tained mechanical loads. Local overstrain is defined in NC-3672.6(b). Evaluation methods and acceptance criteria shall be specified by the Owner.
-3626 Nomenclature A.=total cross-sectional area of pipe based on nominal outside diamDeter, f
, in2 4,-
Ai=predicted inside cross-sectional area for a pipe that has experienced wall thinning, in.2 A.=predicted metal cross-sectional area for a pipe that has experienced wall thinning, in?
A,=predicted metal cross-sectional area of pipe, in.2 A,,t,=the reinforcement area available in the pipe wall based on the predicted thickness distri-bution in excess of rmia and within the limits of reinforcement of the Construction Code for an opening ith diameter,, at the region of local thinning, in D.=nominal outside diameter of piping item (e.g., 10.75 for NPS 10 pipe), in.
d,=maximum outside diameter of a reducer at
.the thinned location, in.
DAoutside diameter at the large end of the reducer, in.
Di= nominal inside diameter of a branch connec-tion, in.
f=stress range reduction factor i=stress intensification factor of tie Construc-tion Code (not less than 1.0)
I Unpredicted minimum moment of inertia of the thinned pipe about the neutral axis of the pipe section, considering all orientations of the section neutral axis, in!
L=maximum extent of a local thinned area with wall thickness less than t,,,, in.
L,,=maximum extent of a local thinned area with wall thickness less than :,,, in.
4,(,)=maxinum axial extent of a local thinned area with wall thickness less than tmi in.
L,,,,,=maximum of the axial extents of two adja-cent local thinned areas with wall thickness less than,,,,, in.
L,( )=maximum transverse extent of a local thinned area with wall thickness less than t:,,,
in.
L,,,,=average of the extents of thickness less than I,,,a for two adjacent thinned areas, in.
Mfb=resulting bending moment from the design analysis of record for each loading condition under consideration, in-lb P=design pressure, psi Rb =bend radius of an elbow to the elbow center line, in.
R.=nominal outside radius (e.g., 2.25 for NPS 4 pipe), in.
Rm',=radius to the nominal outside surface of the pipe plus the nominal distance between the center of the pipe and the neutral axis. in.
Rmii=mean radius of piping item based on the nominal outside radius and the minimum 992 E3-10
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597-1 CASES OF ASMIE BOILER AND PRESSUF.E VESSEL CODE Large end transition zone Central conical
/
section Small end transition zone GENERAL NOTE:
Transition zones extend from the point on the ends where the diameter begins to change to the point on the central cone where the cone angle Is constant.
FIG.-3622-1 ZONES OF REDUCER wall thickness (e.g., 7.85 for NPS 16 pipe with trw
= 0.30 in.), in.
R,,om=mean radius of piping item based on the nominal radius and thickness (e.g., 6.75 for NPS 14 XS pipe with t,
= 0.5 in.), In.
3=allowable stress-for piping item, including joint efficiency factor. E, if applicable, psi.
St = maximum nominal bending stress at the thinned section, psi.
S,-nominal longitudinal pressure stress, psi.
t,,,,=allowable local thickness, in.
tb=uniform. thickness, of piping item, required by the Construction Code, to withstand sus-tAined and occasional bending loadings in the absence of pressure, thermal expansion, and anchor movement loadings, in.
- ,=
inimum wall thickness required by the Construction Code to sustain pressure, ex-clusive of-tolerances and any allowances for corrosion, in.
auenl= tmin for. large end of a reducer, in.
rmmi ip,=tmmn for straight pipe, in.
(,radusted inimum thickness for inner por-tion of an elbow, in.
,, = nominal thickness of pipe or fitting specified in the applicable industry standard for the piping item. For items designed to specified minimum thickness, the nominal thickness is the design thickness, including corrosion allowance and excluding tolerances, in.
r=distribution of predicted local thickness of a piping item at the next scheduled examina-tion, in.
t.pW.=minimum predicted local thickness of a piping item at the next scheduled examina-tion, in.
y=factor required by the Construction Code used in the evaluation Z^1.=predicted minimum section modulus for the thinned section, including consideration of the shift of the neutral axis of the thinned pipe section, ID/R,, in?
a=maximum cone angle at the center of a reducer, degree 8= maximum angle from the center of the outer one-half of the elbow to the location of the thinned area being evaluated, as measured in the pipe cross section, degree
£=nominal distance between the cente of the pipe and the neutral axis of the thinned piping section, in.
993 SUPP. 2 - NC E3-11
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597-1 CASES OF ASME BOLER AND PRESSURE VESSEL CODE tnom t V/////
~~~~I Axiul direction t Transverse I (hoop direction)
FIG. -3622-2 ILLUSTRATION OF WALL THINNING SUPP. 2 - NC 994 E3-12
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued N-597 CASES OF ASME DOELER AND PRESSURE VESSEL CODE diameter FIG. -3622-3 ELBOW AND NOMENCLATURE 995 E3-13
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOMER AND PRESSURE VESSEL CODE t 2 6in in surrounding arqa x1.3 Area 3 ro 3 < rmrnn X- - minimum distance between areas iand J Lm, maximum extent of thinned areai Lm,avg -
05 Lm.I + Lm GENERAL NOTE:
Combination of adjacent areas into an equivalent single area shall be based on dimensions and extents prior to combination.
FIG. -3622-4 SEPARATION REQUIREMENTS FOR ADJACENT THINNED AREAS 996 E3-14
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued N-591 CASES OF ASME BoILER AND PRESSURE VESEL CODE 4
[Note (1)]
X
= minimum distanea between areas iandjat any circumferential location on pipe Lmps)I.
maximum extent of thinned area in axial direction ma maximurn of the extents Lmga and Lmal /of two adjacent areas NOTES:
II) Areas need not be combined Into single areas based on separation in the transverse direction, provided that transverse extents of individual adjacent thinned areas do not overlap.
121 Combination of adjacent areas into an equivalent single area shall be based on dimensions and extents prior to any combination of adjarent areas.
FIG. -3622.5 SEPARATION REQUIREMENTS FOR ADJACENT THINNED AREAS 997 E3-15
ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOILER AND PRESSURE VESSEL CODE TABLE -3622-1 Allowable Local Tickness
-3622.2
-3622.4 O
0.100 0.100 0.20 0.100 0.261 0.23 0.100 0.300 0.26 0.100 0.375 03z 0.100 0.477 0.38 0.100 0.551 OA5 0.100 0.616 0.50 0.100 0.651 0.60 0.100 0.703 0.70 0.182 0.742 0.83 0.300 0.778 0.85 0.315 0.782 0.90 0.349 0.794 1.00 0.410 0.813 1.20 0.505 0.841 1.40 0.572 0.860 1.60 0.622 0.873 1.80 0.659 0.883 2.00 0.687 0.891 2.25 0.714 0.897 2.50 0.734 0.900 2.75 0.750 0.900 3.00 0.7.63 0.900 3.50 0.787 0.900 4.00 0.811 0.900 4.50 0.634 0.900 5.00 0.858 0.900 5.50 0.882 0.900 6.00 0.900 0.900
>6.00 0.900 0.900 GENERAL NOTE:
Interpolation may be used for intermediate valLes.
998 E3-16
V ENCLOSURE 3 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 CODE CASE N-597-1 CASE (continued)
N-597 CASES OF ASME BOILER AND PRESSURE VESSEL CODE TABLE -3625-1 MODIFIED STRESS RANGE REDUCTION FACTORS Number of Equivalent Stress Range Full Reduction Factor 2, f Temperature Cycles1, N 650 or less 1.0
>650 to 1100 0.9
>I100 to 20CO
- 0.
>2000 to 3900 0.7
>3900 to 3500 0.6
>8500 to 21,000 0.5 over 21,000
0.4 NOTES
(1) Cycles to next Scheduled Inspection or repair/replaccment activlty.
(2) The nodified stress range reduction factors are based on an Increase I the stress intensification factor, I by a factor of z over the lfe cf the component.
999 E3-17
ENCLOSURE 4 WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 COMMITMENT LIST
ENCLOSURE 4 WATTS BAR NUCLEAR PLANT (WBN)
UNIT 1 FIRST 10-YEAR INTERVAL REQUEST FOR RELIEF 1-RR-05 COMMITMENT LIST
- 1.
During the Cycle 6 refueling outage, Watts Bar will ultrasonically examine Grid 103BE252 elbow to steam generator Loop 2 inlet nozzle to obtain a new set of UT data, obtain a refined wear rate and perform a new analysis.
E4-1