ML20046C370
| ML20046C370 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/06/1993 |
| From: | Marsh W SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M80698, TAC-M80699, NUDOCS 9308100196 | |
| Download: ML20046C370 (11) | |
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,j Southem Califomia Edison Company 23 PAHKLil SlF4E Ei 154VlNE, CAllrOfINIA 9271fl August 6, 1993 wAtten c uAnso
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MANAQ( H OF 6JU(A3 AH pe[GOL ATOHy Ar p AgHg (7 3 4) agg.4403 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C.
20555 Gentlemen:
i
Subject:
Docket Nos. 50-361 and 50-362 First Ten-Year Interval Inservice Inspection Program i
San Onofre Nuclear Generating Station Units 2 and 3
References:
1.
March 20, 1992, letter from H. E. Morgan (SCE) to the Document Control Desk (NRC),
Subject:
First Ten-Year Interval Inservice Inspection Program, San Onofre Nuclear Generating Station, Units 2 and 3 2.
December 3, 1992, letter from T. R. Quay (NRC) to H. B. Ray (SCE),
Subject:
Inservice Inspection Relief Requests B-7, B-8, B-9, and Code Case N-481 for San Onofre Nuclear Generating Station, Units 2 and 3 (TAC NOS. M80698 and M80699)
This letter provides a revision to the San Onofre Units 2 and 3 Inservice Inspection Program for the number of welds to be inspected during the First Ten Year Interval. We reviewed our program, as stated in reference 1, which resulted in reducing the number of Category C-F welds selected for examination.
In addition to this reevaluation, we revalidated the weld population, which also resulted in changes to the program.
t BACKGROUND t
Relief Request B-8, submitted by reference 1, requested relief from the ASME Code, Articles IWB-2400 and IWC-2400, " Inspection Schedule," for examination of Class 1 and 2 welds, respectively. The ASME Code requires completion of a minimum of 50 percent of the required "1/3-volumetric-plus-surface" l
examinations by. the end of the second inspection period in the first inspection interval. Approximately 80 percent of the Category B-J and C-F welds had received a full volumetric examination. However, the Code-required surface examinations of 50 percent of those welds selected had not been performed by the end of the second inspection period of the first interval.
This relief request was approved by reference 2.
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@b 9308100196 930806 g
l PDR ADOCK 05000361 G
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Document Control Desk
- As discussed in Relief Request B-8, we combined the requirements of the 1974 Edition,1975 Addenda as directed by 10CFR 50.55 (a) for the selection of C-F welds in the Residual Heat Removal (RHR), Emergency Core Cooling (ECC), and Containment Heat Removal (CHR) systems and the 1977 Edition, Summer 1979 addenda which San Onofre Units 2 and 3 were committed.
We conservatively i
applied both Codes for the selection of the welds.
A table of the Class 1 anc. Class 2 piping welds selected for examination for the First Ten Year Interval was attached to Relief Request B-8.
This table is provided as Enclosure 1.
A second table, Enclosure 2, is provided to show the changes to the program and the explanations for the changes.
Red-line, strike-out, and bold print are used to help identify the changes and group the changes with their respective explanations.
I DISCUSSION The tables in both Enclosure 1 and Enclosure 2 are separated into three sections.Section I lists Category B-J welds.Section II lists the Category C-F welds not in the RHR, ECC, and CHR systems, and Section III lists the Category C-F welds in the RHR, ECC, and CHR systems.
Section I Chanaes The number of Category B-J welds was not reduced, but minor corrections were made to the table. These corrections were due to some design changes implemented subsequent to the original program selection.
Section II ChanaesSection II of Enclosure 1 lists 225 Category C-F welds.
This number includes welds selected for the Augmented Inservice Inspection of high energy fluid system piping.
Because the Augmented Inservice Inspection program requires volumetric examination only, as specified in Section 6.6.10 of the UFSAR, not all of the 225 welds require a surface examination.
Following reevaluation'of the program, the Category C-F welds not in the RHR, ECC, and CHR systems were selected for surface examination using the 1977 Edition, Summer 1979 Addenda of the ASME Code,Section XI, Table 2500-1.
Therefore, as shown in Enclosure 2, the number of Category C-F welds not in the RHR, ECC, and CHR systems that will receive a surface examination is now 143 instead of 225.
The remaining 82 welds have been or will be inspected only according to the Augmented Inservice Inspection Program (volumetric examination only) described in Section 6.6.10 of the UFSAR.
Section III Chances i
Section III of the enclosures concerns the Category C-F welds in.the RHR, ECC, and CHR systems.
In Enclosure 1, the original number of welds, 819, was selected by the conservative approach of selecting 100 percent of the weld population in the above systems.
7 Document Control Desk -
10CFR50.55a(b)(2)(iv) requires the examination of welds in Class 2 RHR, ECC, and CHR systems in accordance with paragraph IWC-1220, Table IWC-2520 Category C-F, and paragraph IWC-2411 of the 1974 Edition of Section XI of the ASME Code with Addenda through Summer, 1975.
Paragraph IWC-2411 states that the required examinations shall be completed by the end of the service lifetime, but divided among the number of inspection intervals.
Paragraph IWC-2420 of the 1977 Edition of Section XI, however, states that components examined during the first inspection interval should be examined, to the extent practical, during each succeeding inspection interval. Because i
of the apparent contradiction between the requirements, we had conservatively I
chosen to examine all welds during each inspection interval.
Following the reevaluation, the Inservice Inspection Program now schedules Category C-F welds in the RHR, ECC, and CHR systems to be examined strictly in accordance with paragraph IWC-1220, Table IWC-2520 Category C-F, and paragraph IWC-2411 of the 1974 Edition of Section XI with Addenda through Summer, 1975 as required by 10 CFR 50.55(a).
Therefore, the number of welds selected for inspection in the first interval has been reduced from 819 to 366.
Chanaes ADolicable to Sections II and III l
In addition to the reduction in the number of welds selected for inspection, also explains increases in the total weld population between the original program and our current program. This weld population increase is due to plant design changes since the original program was developed and a 4
review of certificate of material test reports which indicate the existence of longitudinal welds not identified on any drawing. These changes are the result of an extensive program review recently performed to ensure all existing welds subject to inspection are included in the program.
If you have any questions, please call me.
Sincerely,
[h0 i
l cc:
B. H. Faulkenberry, Regional Administrator, NRC Region V C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2&3 l
H. B. Fields, NRC Project Manager, San Onofre Units 2 and 3
-i - '
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i Class 1 and Class 2 Piping Welds i
First 10-Year Inservice Inspection Program Subject to Relief Request B-8 NOTE: the following numbers are taken from the San Onofre Unit 2 program. The Unit 3 program is similar but not identical.
t I.
ASME Code Class 1, Category B-J Welds A.
Carbon Steel Welds Outside Reactor Shield Cavity:
31 Circumferential 36 Longitudinal 67 Welds B.
Stainless Steel Welds
- 1. RPV Closure Head Instruments:
20 Circumferential l
- 2. Pressurizer Fittings:
1 Circumferential
- 3. Pressurizer Surge Line:
4 Circumferential
- 4. Pressurizer Safety Valve piping:
4 Circumferential
8 Circumferential
- 6. Safety Injection Piping:
- a. 12" pipi g:
33 Circumferential-1 b.
8" piping:
20 Circumferential i
c.
4" piping:
2 Circumferential
- 7. Shuidown Cooling Inside Containment:
- a. 18" piping:
2 Circumferential
- b. 16" piping:
4 Circumferential 4 Circumferential
- c. 10" piping:
- 8. Pressurizer Spray Line Piping:
- a. Spray Line from RCS Loop 1A:
10 Circumferential
- b. Combir.cd Spray Line:
4 Circumferential
- c. Splay Llae from RCS Loop 1B:
4 Circumferential 120 Welds l
t SUBT0TAL FOR ASME CODE CLASS 1 CATEGORY B-J = 187 WELDS i
1
-THIS TABLE WAS SUBMITTED ON SEPTEMBER 24, 1991, AND AGAIN ON MARCH 20, 1992 1
'I I.
ASME Code Class 2, Category C-F Welds A.
- 1. Category C-F Welds Inside Containment
- a. Nozzle-to-Pipe Welds:
2 Circumferential l
- b. 40" piping:
1 Circumferential j
- c. 20" piping:
8 Circumferential
- d. 18" piping:
3 Circumferential e.
6" piping:
8 Circumferential
- f. other:
3 Longitudinal t
25 Welds
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- 2. Category C-F Augmented ISI Inside Containment
- a. Nozzle-to-Pipe Welds:
2 Circumferential i
- b. 40" piping:
6 Circumferential
- c. 20" piping:
4 Circumfr rential d.
6" piping:
59 Circumferential i
- e. other:
15 Longitudinal 86 Welds
- 3. Category C-F Augmented ISI Outside Containment
- a. Circumferential welds:
95 Circumferential
- b. Longitudinal welds:
Stainless Steel Welds
- 1. C-F Welds Inside Containment
- a. Regenerative Heat Exchanger:
9 Circumferential
- b. Letdown Delay Mechanism:
2 Circumferential 3
l 11 Welds SUBTOTAL FOR ASME CLASS 2 CATEGORY C-F = 225 WELDS
)
I l
THIS TABLE WAS SUBMITTED ON SEPTEMBER 24, 1991, AND AGAIN ON MARCH 20, 1992
'III.
ASME Code Class 2, Category C-F Welds in Residual Heat Removal (RHR),
Emergency Core Cooling (ECCS), and Containment Heat Removal Requiring Examination as Specified by 10CFR50.55a(b)(2)(iv) gHR) Systems
- 1. C-F Welds in Safety Systems Inside Containment
- a. Circumferential welds:
31 Circumferential
- b. Longitudinal welds:
20 Longitudinal 51 Welds
- 2. C-F Welds in Safety Systems Outside Containment
- a. Circumferential welds:
536 Circumferential
- b. Longitudinal welds:
231 Longitudinal
- c. Valve Body 1
768 Welds SUBTOTAL FOR CLASS 2 SPECIFIED BY 10CFR50.55a(b)(2)(iv) = 819 WELDS TOTAL OF ASME CLASS 1 AND 2 WELDS SUBJECT TO RELIEF = 1231 WELDS Note (a):
The welds in this category have been selected to meet the requirements of 10CFR50.55a(b)(2)(iv) to examine welds in Class 2 RHR, ECCS and CHR systems in accordance with the extent specified in paragraph IWC-1220, Table IWC-2520 Category C-F and paragraph IWC-2411 of the 1974 Edition of Section XI with Addenda through Summer, 1975 Addenda.
Paragraph IWC-1220 specifies which components may be exempted from examination is summarized as follows:
1.
Components 4" and less in nominal pipe size 2.
Components in systems where both the design temperature is equal to or less than 200*F and the design pressure is less than or equal to 275 psig.
3.
Components other than emergency core cooling systems which do not function during normal reactor operation.
Table IWC-2520 specifies that the following non-exempted welds in Category C-F shall be examined:
1.
Circumferential butt welds at structural discontinuities (defined as including weld joints at pipe-to-vessel nozzle joints, pipe-to-valve body joints, pipe-to-pump casing joints and pipe-to-fitting joints) 1 THIS TABLE WAS SUBMITTED ON SEPTEMBER 24, 1991, i
AND AGAIN ON MARCH 20, 1992
Note (a):
continued 2.
Circumferential butt welds in piping within 3 pipe diameters of the centerline of rigid pipe anchors, or anchors at the penetration of the primary reactor containment, or at rigidly anchored components.
3.
Longitudinal weld joints in pipe fittings 4.
Branch connection weld joints
+
5.
Pump casing and valve body welds Paragraph IWC-2411 states that the required examinations shall be completed by the end of the service lifetime, but divided among the number of inspection intervals.
Paragraph IWC-2420 of the 1977 Edition of Section XI, however, states that components examined during the -first inspection interval should be examined, to the extent practical, during each succeeding inspection interval.
Because of the seemingly contradictory nature of the requirements, we have conservatively chosen to examine all welds during each inspection interval. This decision to examine all welds during each inspection interval is being reassessed and will be the subject of future correspondence if we alter our approach.
i l
j THIS TABLE WAS SUBMITTED ON_ SEPTEMBER 24, 1991, AND AGAIN ON MARCH 20, 1992
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ENCLOSURE 2~
PAGE 1 0FL4 Class 1 and Class 2 Piping Weids First 10-Year Inservice-Inspection Program
' NOTE: the following numbers are taken from the San Oncfre Unit 2 program.
The Unit 3 program is similar but not identical.
ORIGINAL NEW SELECTION SELECTION
't I.
ASME Code Class 1, Nominal pipe size (NPS) 4" and greater, Branchip"ip"eTconnett'ionNsidfiNPSisrehteMthan*2;"".
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Category B-J. We1ds A.
Carbon Steel Welds Outside Reactor Shield Cavity:
31 Circ.
31 36 Long.
36 67 Welds 67 B.
Stainless Steel Welds 1.
RPV Closure Head Instruments:
20 Circ.
20 2.
Pressurizer Fittings:
1 Circ.
1 3.
Pressurizer Surge Line:
4 Cire.
4
- 4. _ Pressurizer Safety Valve piping:
4 Circ.
4 5.
8 Circ.
8 i
.6.- Safety-Injection Piping:-
l a.
12" piping:
33 Circ.
33 b.
8" piping:
20 Circ.
20 c.
4" piping:
2 Cire.
2 7.
Shutdown Cooling Inside Containment:
a.
18" piping:
2 Circ.
2 b.
16" piping:
'4 Circ.
4 c.
10" piping:
4 Circ.
-4 8.
Pressurizer Spray Line Piping:
- a. -Spray Line from RCS Loop 1A:
10 Circ.-
8 b.
Combined Spray Line:
4 Circ..
t
_4 c.
Spray Line from RCS Loop 1B: _
4 Cire.
6
~120 Welds 120 CHANGES DUE TO DESIGN CHANGES IMPLEMENTED SUBSEQUENT TO THE ORIGINAL PROGRAM
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ENCLOSURE 2 PAGE 2 0F 4 r
ORIGINAL NEW SELECTION SELECTION SUBTOTAL FOR NPS 4" AND GREATER, AND BRANCH PIPE CONNECTION WELDS NPS GREATER THAN 2"IN ASME CODE CLASS 1 CATEGORY B-J=
187 WELDS 187 ORIGINAL WELD NEW SELECTION POPULATION SELECTION II.
ASME Code Class 2, Category C-F Welds A.
Category C-F Welds Inside Containment a.
Nozzle-to-Pipe Welds:
2 Circ.
4 2
b.
42" piping:
7 2
PART OF ORIGINAL PROGRAM BUT INADVERTENTLY LEFT OFF TABLE E M 40"ilipihgy * " I " "^?
""?" WCl'rbf ' ~21E""""58 i
dd20$pipingO 18.!Circw J l301 s i8
.f M. n "{pj,pmgp,;
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63lCirch J16}
J4 e.518"jpiping:
287Cire?
J,113 w.WHERE?6"iWELDSTARE"FOUNO:0NIPIPINCRUNS, J
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u.n a c a.5..126; m..
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p OUTSIDE! CONTAINMENT @lTHEtWELDS1 SELECTED FORlilNSPECTION! WERE :i PRIMARILYiOUTSIDE" '
CONTAINMENT!("SEE131 ai bel oQ"68Wel d s)]
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ENCLOSURE 2 PAGE 3 0F 4 ORIGINAL WELD NEW SELECTION POPULATION SELECTION 3.
Category C-F WELDS ^UCMENTED ISI Qutside Containment a.
Circumferential welds:
95 Circ.
156 68 NO LONGER INCLUDES AUGMENTED ISI ALSO SOME WELDS ARE ASSOCIATED WITH 1.f. ABOVE b.
Longitudinal welds:
8 Long.
24 10 NO LONGER INCLUDES AUGMENTED ISI 103 Welds 180 78 B.
Stainless Steel Welds 1.
C-F Welds Inside Containment a.
Regenerative Heat Exchanger:
9 Circ.
9 9
b.
Letdown Delay Mechanism:
2 Circ.
2 2
11 Welds 11 II SUBTOTAL FOR ASME CLASS 2 CATEGORY C-F =
225 WELDS 431 143 ASME Code Class 2, Category C-F Welds in Residual Heat Removal (RHR), Emergency Core Cooling )(ECC), and III.
Containment Heat Removal (CHR) Systems Requiring Examination as Specified by 10CFR50.55a(b)(2 (iv) M 1.
C-F Welds in Safety Systems Inside Containment a.
Circumferential welds:
31 Cire.
31 10 SELECTED USING 1974 CODE WITH ADDENDA THROUGH SUDMER 1975 CRITERIA b.
Longitudinal welds:
20?tbnaF ^T34?" "*"" qq}"iPOPULATIONiCHANGEDIDUEET0! LONGITUDINAL 51 Welds *
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'30 WELDSIADDEDiBY! REVIEW;0F@ERTIFICATE[0B NATERI AGTEST6 REPORTShSELECTION 5THEN(MADE USING1!1974iCODE) WITHE ADDENDAQHROUGg ~"
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ENCLOSURE 2 PAGE 4 0F 4 ORIGINAL WELD NEW SELECTION POPULATION SELECTION 2.
C-F Welds in Safety Systems Outside Containment a.
Circumferential welds:
536 Circ.
565 174 POPULATION CHANGE DUE TO DESIGN CHANGES IMPLEMENTED. SUBSEQUENT TO THE ORIGINAL PROGRAM. SELECTION THEN MADE USING 1974 CODE, WITH ADDENDA THROUGH SUtMER 1975, CRITERIA THE! MAJ0RITY;0FfTHEjPOPULATIONICHANGED700E b2)3%ongitudinalsweldsii ' "
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Qllitbng}j;678yg
_., A158g.TO?LONGITUDINAt#WELDSIADDED!BYtRE CERTIFICATEiOFiMATERIALBTEST!REPORTSjAND
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SOMEi.WEREfADDEDiBYsDESIGNiCHANGE5h SELECTION 3THEN ?MADEdUSINGil974) CODE 7?WITH ADDENDAlJH g i g [$j}((pj{pR1,TERI f **
c.
Valve Body Welds 1
4 4
REVIEW OF THE PROGRAM SHOWED THAT THESE 768 Welds 1247 336 WELDS HAVE ALREADY BEEN INSPECTED SUBTOTAL FOR CLASS 2 SPECIFIED BY 10CFR50.55a(b)(2)(iv) =
819 WELDS 1312 366 TOTAL OF ASME. CLASS 1 AND 2 WELDS SUBJECT TO RELIEF =
1231 WELDS NOT APPLICABLE TOTAL OF ASME CLASS 1 AND 2 WELDS SELECTED FOR INSPECTION =
1231 WELDS 2245 696
.