ML20205F574
| ML20205F574 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/29/1999 |
| From: | Leach D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20205F577 | List: |
| References | |
| BVY-99-43, NUDOCS 9904060320 | |
| Download: ML20205F574 (4) | |
Text
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a VERMONT YANKEE 0"y NUCLEAR POWER CORPORATION 185 Old Ferry Road, Brattleboro, VT 05301-7002 (802) 257-5271 March 29,1999 BVY 99-43 U.S. Nuclear Regulatory Commission ATfN: Document Control Desk Washington, DC 20555
References:
(a) Letter, VYNPC to USNRC, " Jet Pump Riser Circumferential Weld Inspections,"
BVY 98-67, dated May 4,1998.
(b) Letter, USNRC to VYNPC, " Request for Additional Information Regarding Jet Pump Riser Circumferential Weld Inspections at Vermont Yankee Nuclear Power Station (TAC No. MA1681)," NVY 98-77, dated June 3,1998.
(c) Letter, VYNPC to USNRC, " Response to Request for Additional information regarding Jet Pump Riser Circumferential Weld Inspections," BVY 98-112, dated July 30,1998.
(d) Letter, USNRC to VYNPC, " Jet Pump Riser Circumferential Weld Inspections At Vermont Yankee Nuclear Power Station (TAC No. MA1681)," NVY 98-153, dated October 26,1998.
Subject:
Vermont Yankee Nuclear Power Corporation License No. DPR-28 (Docket No. 50-271)
Jet Pump Riser Circumferential Weld InSDeetIons and Flaw Evaluation In Reference (a) Vermont Yankee provided the NRC with information concerning the Spring 1998 refueling outage examination of the jet pump riser welds and the discovery of four flaws, in Reference (b) the Staff requested that Vermont Yankee provide additional information with regard to those inspections. In Reference (c) Vermont Yankee provided a response to each of the Statf's questions. In Reference (d) Vermont Yankee received a Safety Evaluation from the NRC for operation without repair for one cycle. This letter seeks to extend the reinspection period from one cycle to two cycles. It supplies similar information to that contained within References (a) and (c), but with modifications based on a reanalysis of the jet pump loads with the existing flaws. The initial
/
analysis used in Reference (a) was an expedited conservative analysis, while the new analysis provides the final flaw handbook evaluation.
In preparation for the 1998 refueling outage, Vermont Yankee contracted for the design and deployment of a new tool to volumetrically inspect all thirty (30) jet pump riser circumferential welds using ultrasonic testing (UT) techniques. Inspection techniques were qualified and were to be performed in accordance with the BWRVIP Guideline-41,"BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines." The subject welds are numbered RS-1 (thermal sleeve to riser elbow),
RS-2 (elbow to riser), and RS-3 (riser to transition piece).
b O
9904060320 990329' PDR ADOCK 05000271 P
- PDR, 1
e Vamon Ymtli Nnuun Powrn Cmmonmos BVY 99-43 / Page 2 During the 1998 outage, twenty six (26) of the thirty (30) subject welds were UT inspected. Due to interferences, four welds (one RS-1 weld and three RS-3 welds) were inspected using modified VT-1 inspection techniques. He welds were cleaned prior to visual inspection.
The UT inspections identified a flaw indication in four of the RS-1 welds. Attachment 1 provides excerpts of the final inspection report and includes data for flawed welds N2B-RS-1, N2C-RS-1, N2H-RS-1, and N2K-RS-1. The flaws were sind at 2.82",2.82",0.84", and 2.82" respectively. In addition j
to the identified flaw sins, a flaw measurement uncertainty of 0.191" was added to each end of the flaws for the evaluation process. Flaw lengths and locations wore reviewed in detail and verified for accuracy for each weld.
Measurement uncertainty was determined in accordance with BWRVIP-03, General Procedures 2.3,
" Guidelines for Determining NDE Technique Uncertainty," and 2.4, " Guidelines for Determining Inspection Tool Positioning Uncertainty." He demonstration was partially conducted at the EPRI NDE Center in Charlotte in early 1997 and was then con?oleted on site at Peach Bottom Atomic Power Station in October,1997. EPRI pewnnel witnessed tia demonstration and then performed the uncertainty determination. The evaluation factor for NDE us.fertainty for the 60' probe is 0.164".
The evaluation factor for the delivery system uncertainty is 0.04" These two values are added together to give sa NDE system evaluation factor of 0.191" which is then added to each end of a flaw.
]
A " Flaw Handbook" has been developed by General Electric for Vermont Yankee to identify the critical flaw sin for each of the jet pump circumferential welds (Attachment 2). This " handbook" has been revised since the previous submittals, References (a) and (c). It was determined that the RS-1 welds could contain a flaw as large as 18.62" long and still satisfy structural integrity requirements.
Additional conservative calculations were performed relative to the detected flaw length. Allowing for measurement uncertainty it was also determined that a flaw of 3.20" length could (worst case) grow to 5.61" over the next two operating cycles (Attachment 3), taking into account maximum possible flaw gmwth as a result of intergranular stress corrosion cracking. As can be seen from j, this value does not approach the threshold value beyond which flow induced vibration i
(FIV) crack growth initiates,8.16" for RS-1. Using the guidance of BWRVIP-41, leakage thrcugh the j
maximum calculated crack was calculated and appropriately integrated into the affected analyses.
t The allowable crack sin due to FIV is a threshold value beyond which fatigue crack growth initiates.
Any initial flaw sim is susceptible to IGSCC only. Herefore, the inspected as-found flaw sin plus NDE uncertainty and IGSCC crack growth constitute the end-of-cycle adjusted flaw sin. Moreover, the crack growth due to fatigue initiates when the adjusted flaw sin exceeds the FIV threshold values.
The estimated fatigue crack growth due to FIV is aro because the adjusted flaw sins for the next two fuel cycle at Vermont Yankee are less than the FIV threshold values.
The detected flaw lengths and conservatively projected flaw growth over the next two operating cycles are therefore well within the envelope of acceptability fbr continued operation with regard to structural integrity and corresponding leakage.
Based upon the above and the attachments provided, it is demonstrated that jet pump riser integrity and performance is not compromised for at least the next two operating cycles. It is anticipated that these flawed welds will be reinspected during the 2001 refueling outage and further evaluated.
1 VI'.l(M()NT YANKl'.l:. Nt t:.i'.Ait l't>ws.it C<piti><>itAliciN I
BVY 99-43 / Page 3
)
We trust'that t!ae enclosed information is responsive to your concerns. If you have any questions on this transmittal, please contact Mr. Thomas B. Silko at (802) 258-4146.
Sincerely, VERMO A
NUCLEAR POWER CORPORATION t
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Vic Pr
- ent, Engineering Attachments cc:
USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS 3
USNRC Project Manager-VYNPS Vermont Department of Public Service 1
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Vnnuost YAnim Necirrn Powru Coni >on.uioN Docket No. 50-271 BVY 99-43 I
l l
Vermont Yankee Nuclear Power Station Jet Pump Riser Circumferential Weld Inspections and Flaw Evaluation Inspection Results
GE NuclearEnergy I
i Final Report Vermont Yankee Nuclear Plant Unit 1 Recirculation inlet Riser Ultrasonic Examination Prepared for Vermont Yankee Unit 1 Prepared by:
GE Nuclear Energy Report No.1HQXE:, Rev. O April 1998 Prepared By:
Date:
b !iYI Jdhn J. Hayden, GEInsp'ection Services Level til
~
Date:
((
Reviewed By:
Stephen Evemtt, GEInspection Services Project Manager h
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Report 1HQXE, Rev. 0 1998 Vermont Yankee Recirculation Inlet RiserExarnination
i
O GE Nuclear Energy Project Summary During the time period from 1 April through 3 April 1998, General Electric inspection Services conducted ultrasonic examinations of Recirculation inlet Riser welds at Vermont Yankee, Unit 1.
The scope of the examinations included welds RS-1, RS-2 and RS-3 on Recirculation inlet Risers N2A through N2K. The ultrasonic examinations were performed at the request of Vermont Yankee.
This report contains specific details regarding the perfumance and results of the examinations.
References The ultrasonic examinations described in this report are not addressed by the ASME Code. The examinations were performed in accordance with the intent of ASME Sections V and XI with regard to the basic ultrasonic requirements, whenever possible.
General Ele' tric document UT-VMY-516, Version 2, " Procedure for Automated c
Ultrasonic Examination of Recirculation inlet Riser Piping Welds internal to the RPV."
General Electric document 386HA480, " Certification of Nondestructive Test Personnel *.
]
e BWRVIP-03 Document, Draft Section 2.6.
General Electric Quality Assurance Manual, QAM-003.
Eautoment Smart 2000 Acquisition System The Smart 2000 data acquisition system was utilized for this examination. The Smart 2000 is an eight channel multiplexed, digital system. The system digitizes the entire RF wave form at the rate of up to 80 MHz. The entire A-scan is digitized and archived to optical disk for off-line analysis review and comparison of subsequent examinations.
JPR-2000 Delivery System The JPR-2000 is installed on the component using a long pole and an underwater camera to aid in the proper placement of the scanner. The device attaches to the vertical piping member of the inlet Riser Assembly. The search units are positioned the appropriate side of the weld joint and are then manipulated in a rectangular raster scan pattem about the entire circumference of the weld. This scanning motion provides volumetric coverage of the weld and HAZ on both sides of the weld.
Report 1HQXE, Rev. 0 1998 Vermont Yankee Recirculation INet Riser Eamination
L 9
'GE Nuclear Energy i
l l
Smart 2000 Data Analysis Workstation The Smart 2000 Workstation is employed for the evaluation of ultrasonic data. The data is displayed with any combination of time (or amplitude)in A-scan, B-scan and C-scan views.
The color palette for data display and analysis purposes is adjustable. Preset color palettes i
can be used for amplitude evaluation, or adjustments can be made to enhance the B or C-scan display. Aojustable gates can be altered in either time or amplitude to re-display the C-scan image allowing the analyst to accentuate and focus on an area of concem.
Examination Methodoloav The examinations employ two 60* shear wave search units which are offset circumferentially by 180' Scanning is performed from one side of the weld. The search units are positioned the appropriate side of the weld joint and are then manipulated in a rectangular raster scan pattern about the entire circumference of the weld. The ultrasound is directed to examine the volume of interest as depicted below:
60 Degree shear waw
,, 1.69in,
,, 0.75 in,,
~~l N X Y W Flow Weld RS-1 60 Degree shear wa*
,, 1.69in,
,, 0.75 in m,
r, r
.Q
- .gC Pe 0#
Weld RS-2 60 Degree stear Q.75 in.,
ga" 1.69in,,
kp, Transistion Piece p;gw 1
Weld RS-3
= BWRVlP-03 Recommended Examination Volume j
i i
Report 1HQXE, Rev. 0 1998 Vermont Yankee Reci ateninlet RiserExaminathn
I l
G,
GENuclearEnergy l
General Layout of Recirculation Riser Welds l
n Weld RS-3 l
Riser Pipe-to-Trarsition Piece Vessel Shell usamunimum Riser Brace
+
t-l Recirculation Inlet Nozz!e Weld RS-2 l
II Elbow to-Riser Pipe J
, \\ Weld RS-1
{
Thermal Sleeve-to-Elbow 1
I
}
Examination Results The examinations resulted with the detection of four flaws. These flaws are confined to the Thermal Sleeve-to-Elbow configuration (designated as Weld RS-1) of the riser inlet riser asserhblies N23, N2C, N2H and N2K. The locations of the detected flaws (as seen looking in the direction of flow) along with their ultrasonic images, are illustrated below:
.. c, 2,.u, i, e,
Weld 270.62*
Weld j
[
N2H-RS1 N28-RS1 3,,,,3, 227.10' (E97 ts'
__89___l ' M aw W 12:
aac-rsi c J..at35 s, Weld W eld N2K-RS1 N2C-RS1 227.16' 4 134.06' 197.19'
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Report 1HQXE, Rev. 0 1998 Vermont Yankee Recirculaten Inlet RiserExamination
'GE Nuclear Energy Table of Ultrasonic Examination Results I
kM bb,,D. )
N2A-RS 1 210' Thermal Sleeve-to-Elbow Geometric Indications N2A RS-2 210*
Eibow-to-Pipe Geometric Indications N2A RS-3 210*
Pipe-to-Transition Piece Geornetric Indications N28-RS-1 240' Thermal Gleeve-to-Elbow Fiaw indication detected on elbow side of weld from 197.19: to 227.16' Length = 2.82*
N28 RS 2 240' Elbow-to-Pipe l Geometnc Indications N28-RS-3 240' Pipe-to-Transition Piece l Geometric Indicrtions
~
N 2C-RS-1 270*
Thermal Sleeve-to-Elbow Flaw indication detected on elbow side of weld from 197.19' to 227.16' Length = 2.82*
N2C-RS 2 270*
l Elbow-to-Pipe l Geometric Indications N2C-RS 3 270*
Pipe-to-Transition Piece l Geometric Indications N 2D-RS-1 300*
Thermal Sleeve-to-Elbow l Geometric Indications N 2D-RS-2 300*
Elbow-to-Pipe l Geometric Indications N20-RS-3 300*
Pipe-to-Transition Piece Not Examined - Lack of Access - Specimen holder orevents oroperinstallation of scanner N2E-RS 1 330' l Thermal Sleeve-to-Elbow Geometric Indications N2E-RS-2 330' l Elbow-to-Pipe Geometric Indications N2E-RS-3 330' l Pipe-to-Transition Piece Geometric Indications N2F-RS-1 30' Thermal Sleeve-to-Elbow Geometric Indications N2F-RS 2 30' Elbow-to-Pipe Georrietric Indications N2F-RS-3 30' Pipe-to-Transit.cn Piece Net Examined - Lack of Access - Jet Pump clearance prevents installation of scanner N2G RS-1 60*
Thermal Sleeve-to-Elbow Not Examined - Lack of Access - Unique elbow location prevents crocerinstallation of scanner N2G-RS-2 60*
l Elbow-to-Pipe Geometric Indications N2G-RS-3 60*
l Pipe-to-Transition Piece Geometric Indications N2H-RS-1 90*
Thermal Sleeve-to-Elbow Flaw indication detected ca elbow side of weld from 261.63' to 270.62* Length =0.84*
N2H RS-2 90*
Elbow-to-Pipe Geometric Indications N2H-RS 3 90*
Pipe-to-Transition Piece Geometric Indications N2J-RS-1 120' Thermal Sleeve-to-Elbow Geometric Indications N 2J-RS-2 120' Elbow-to-Pipe Geometric tr*.stions N2J-RS 3 120' Pipe-to-Transition Piece Not Examined - Lack of Access - Specimen holder prevents procer installation of scanner N2K RS-1 150' Thermal Sleeve-to-Elbow Flaw indication detected on elbow side of we!d from 104.11' to 134.08' Length =2.82*
N2K-RS-2 150*
Elbow-to-Pipe Geometric Indications l
N2K-RS-3 150' Pipe-to-Trans; tion Piece Geometric Indications l
I 1
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Report 1HQXE, Rev. 0 1998 Vermont Yankee Recirculation Inlet R4er Examination I
L
ULTRASONIC EXAMINATlON DATA SHEET
' GE_ Nuclear Energy (AUTOMATED with Smart 2000)
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a..=.._4-..-.. n ygce j REPORT NO.: WCXE PROCEDURE NO.:
GE VMY-516V'
- DATA SHEET NO.
0 <4 l CALIBRATION SHEET NO.:
c.010? m c4
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N29 RS 1 Azimuth:
2@
Component:
T-St e gyg _ ptow ELBOW E a m S a. sce:
C2 Diameter-10e5" Circumforence:
m ac Degrees! Inch:
l',o em" Nomical Tmekness:
0 '.A' 5" Scan size "X":
11 84*
Scan size "Y";
180*
Filename:
N20 Rst Tnarm eme:er SIN:
1 7" & 80 Exam Temperature:
92 F Remarks:
g!ri:- ;i:C. p, iOR312: P3 l LXpl 0.00 Xgl 11.84laXl 11.84 i Z l??l l
l 6 70 Yal 6.70 ExaminatlOn Results:
Yn 191.03 aVl 184.33 Re;;criaele Ir:dicabces C
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4 Yes No L
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I n; i 0.00 LM 55.62l deg HalfPath l
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@ ri:-r3 h ; P 60L311: P1 6 Xg 0.00 Xn 11.% aX ii.WT Z i
i l S I9 Ya 186.70 Flaw y,y 371.03
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aY 184.33 E
Z Yes No i
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HalfPath I
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- ULTRASONIC EXAMINATION DATA SHEET lGE Nuclear Energy (AUTOMATED with Smart 2000)
! REPORT NO.:
PROCEDURE NO.:
G E.VMY.S t SV2 1wCX:
S..,
__r;:.'.N* YANKEE DATA SHEET NO.:
007 7,
Iwayg CALIBRATION SHEET NO.:
C4102 C3 C.s wed 10-N 2C.R $.1 A2imuth:
270' Component:
T.SL EEVE F W ELBOW _ _ _
Etam Sur ace:
00 Diameter: 10 ES' Circumforr nce:
33 4.t" Degrees / Inch; t
- 0 023" d
N:m.n al inickness 0 385
Scan size "X":
10*
Scan size "Y";
180*
Filename:
N2C.R S t
""cr nometer S,N:
1780.*O Exam Temperature:
02 F Remarks:
[ ri:-r5I:C-P,608312: P3 b Xgl 0.00]Xnl 9.99 aX 9.99 [ Zl l
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- U Yd 6.70 Examination ReSults:
Ynl 132.53) aY 185.83
- j Rerrtacle inoicaeans l } '_-
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Yes No I
I i l'!ilj l :+: J 0 00 1/1
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55.62l deg Half Path l
- r.1:-rs1:C; P,60L311: Pi
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186.70 Raw Y l 3725F Reportacte M
ineica r s aY 185.83 g
Yes No 1
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i l-l 195 0ll lllh
.mh..m l ':+; !!
0 00 1/1 55.62l deg HalfPath Qd;h T~ d d-fl N/A
, DxNM4ER LEVEL DATE GEINDEPENDENT REVIEW DATE I/#
fI PAGE:
_OF:
CE REV15WEO BY LEVEL DATE UTILITY MMEW DATE
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ULTRASONIC EXAMINA TION DATA SHEET GE Nuclear Energy (AUTOMATED with Smart 2000)
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REPORT NO : 1 HOVE PROCEDURE NO.:
GE VMY-Stsv7 DATA SHEET NO.:
0427 g; F0 IwCXE CAllBRATION SHEET NO.:
C-0102 m 04 t
Weic : :
N2WRS1 Azime'.h:
M*
Component:
T.S t_E E VE Flow EL90W Esam Sar ace:
QQ Olameter:
10 e5" Circumference:
't3 44" Degrees / Inch: t '.O r323" d
N:m:nal Thickness:
O'E' Scan size "X":
10*
Scan size "Y":
180*
Filename:
N2H.R S t Tnermemeter SIN:
17" M Exam Temperature:
92 F Remarks:
h, fl.~.-r!':C; P 60R312: P3
- - Xg 0.00 Xnl 9.99 aX 9.99[Z
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L ' E - -- -
Ya 6.70 ExaminatlOn Results:
Yn 191.03 aY 134.33 lj Recanacle 4
IndicatCn3 Q
K 3
Yes No y
ll lIm
-r51:C; P,60L311: Pi lXg 0.00 Xnl 9.99 aXl 9.951Z.
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11gr Y;
186.70 YM 371.03 indicatens aY 184.33 g
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a rm:NE LEVEL DATE GEINDE8ENDENT REYlEW DATE
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GE REVIEWED BY LEVEL DATE UTILITY REVIEW DATE com.e- =v e
ULTRASONIC EXAMINA TION DATA SHEET E Nxlear Energy (AUTOMATED with Smart 2000)
S:TE., i.".*i.".1L* Y A N KE E PROCEDURE NO :
GE-VMY St SV2
' DATA SHEET NO.: _ OC9 t,.,; 7
^^
REVISION / FRR NO.:
0 poO;E:7 No.: twoXE CALIBRATION SHEET NO.:
CtJ10? co c4
.' 9 4 :1 __,_
N2K-RS 1 Azimuth:
150*
Component:
T-SLE EVE FLCW ELBOW Eiam Sur* ace:
OQ Diameter: 10 65*
Circumference:
J0 44" Degrees / Inch: f*ocar Nominal Tnicaress:
0 365*
Scan sl e "X":
10*
Scan size '"Y":
190*
F!lename:
N2K-R S t Tnermemeter SIN:
17904 Exam Temperature:
92 F Remaras:
@ rI4-r;;: Cz ? 60R312:P3
- Xgl 0.00lXn_ 9.99aXl 9.99l[Zl l??l l
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U0--
Yal 6.70l Examination Results:
Ynl194.03 aY 187.33l j i neom e Indicatons Flaw a
i ve.
No m
it? 0'i U-Halfpath l
@ rik- ;;;C; P 60L311: Pi ll Xal 0.00 Xnl 9.99l aXl 9.99l i Z
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t 15t70T ~
Yal 18U0 y l 372.53l R" *
- g' IndicadCFS aVl 185.83l g
g Yes No i
1 39H0!
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1/1 l 55.62; deg HalfPath f
% V-W-9Y M/A I
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Exmi:Npt LEVEL DATE GEINDEPENDENT REVIEW DATE 8
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LEVEL DATE UTILITY REVIEW DATE p:m eo =w e
veimost nsu.u secuan rowru coni on.u nis Docket No. 50-271 BVY 99-43 i
i Vermont Yankee Nuclear Power Station Jet Pump Riser Circumferential Weld Inspections and Flaw Evaluation Jet Pump Riser Welds Flaw Handbook i