Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555
Attention: Mr. John F. Stolz, Chief Operating Reactor Branch No. 4
Subject: Oconee Nuclear Station Docket Nos. 50-269, -270, -287
Dear Sir:
Pursuant to 10 CFR 50, §50.55a, please find attached a request for relief
from the inservice inspection requirements of Section XI of the 1980 Edition
of the ASME Boiler and Pressure Vessel Code (with addenda through Winter
1980). The five attached requests concern inservice inspections at Oconee
Units 1, 2, and 3 being performed during the second ten year interval.
These requests for relief require payment of a fee for approval as described
in 10 CFR 70, 9170.12. Accordingly, please find attached a check in the
amount of $150.00 as set forth in §170.21.
Very truly yours,
Hal B. Tucker
RFH:slb
Attachment
cc: Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Mr. J. C. Bryant NRC Resident Inspector Oconee Nuclear Station
Ms. Helen Nicolaras Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555
9409240069 840913 PDR ADOCK 05000269 PDR c4ec
DUKE POWER COMPANY OCONEE NUCLEAR STATION - UNITS 1, 2, & 3
REQUEST FOR RELIEF FROM ASHE CODE SECTION XI (WITH ADDENDA THROUGH WINTER 1980) INSERVICE INSPECTION REQUIREMENTS
A. 1. Component for Which Exemption Is Requested:
(a) Name and Number: Core Flood Nozzle-to-Safe End and Safe End-to-Pipe Welds Drawing OM-201-92
Isometrics: System 53A, Iso 1, Part 2 (Unit 1) Iso 2, Part 3 (Unit 1)
Sheet 8, Part 2 (Unit 2) Sheet 8, Part 3 (Unit 2) Iso 15, Part 1 (Unit 3) Iso 16 (Unit 3)
Approximately 40 man-hours would be required to prepare each of the two core flood nozzle safe ends for inspection. The preparation would involve removal of the refueling canal seal plate, shielding bricks, shielding supports in the nozzle area, and insulation. The radiation levels in this area are expected to be 0.5-1 R/hr. An alternative approach is to enter from the bottom of the vessel and build a scaffold approximately 30 feet high to reach the nozzles. This approach would require approximately 80 man-hours, 40 in the 0.5-1 R/hr. area and the other 40 in the 1-2 R/hr. radiation field present at the bottom of the reactor vessel, for a total exposure of 60-120 man-Rem. Shielding is considered impractical in this area. Any remote inspection would require practically the same preparation work.
4. Alternate Examination:
Welds will be inspected by UT from the inside surface. This will provide adequate assurance of weld integrity at the OD surface.
5. Implementation Schedule:
All core flood nozzle-to-safe ends and safe end-to-pipe welds will be inspected at or near the end of the second ten-year interval.
There are four inlet and two outlet nozzle to pipe welds in each Oconee Reactor Coolant System. These nozzles are SA 508 C1. 2, welded to A106 Gr. C pipe. The inlet nozzle welds are 33.50" diameter, 2.33" nominal wall thickness, and the outlet nozzles are 36" diameter, 2.86" nominal wall thickness. These welds will be volumetrically inspected from the inside surface using an immersion ultrasonic technique, which will not require access to the OD surface of
the weld. Preparing these welds for surface inspection will require
removal of the refueling canal seal plate, shielding bricks, shield
ing supports in the nozzle areas, and insulation. This would require
approximately 300 man-hours of work in a 700-1000 MR/hour area for
each unit. Shielding would be impractical in this area due to the limited space and close proximity to the reactor vessel.
4. Alternate Examination:
Welds will be inspected from the inside surface. This will provide adequate assurance of weld integrity at the OD surface.
5. Implementation Schedule:
The outlet nozzle to pipe welds will be inspected during the first inspection period of the second interval. The inlet nozzle to pipe welds will be inspected during the third inspection period of the second interval.
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DUKE POWER COMPANY OCONEE NUCLEAR STATION - UNITS 1, 2, & 3
REQUEST FOR RELIEF FROM ASME CODE SECTION XI (WITH ADDENDA THROUGH WINTER 1980) INSERVICE INSPECTION REQUIREMENTS
C. 1. Component for Which Exemption Is Requested:
(a) Name and Identification Number:
Reactor Coolant System Piping System 50 Main Loop Welds in Ferritic Steel Piping
(b) Function: Circulate reactor coolant from reactor to steam generators and return
(c) ASME Section III Code Class: Class 1
(d) Valve Category: N/A
2. Reference Code Requirement That Has Been Determined To Be Impractical:
ASME Section XI and Appendix III Paragraph 111-3410 "The Basic calibration blocks shall be made from material of the same nominal diameter and nominal wall thickness as the pipe to be examined."
3. Basis for Requesting Relief:
The main reactor coolant loop piping at Oconee consists of two 36" ID, 2.86" nominal wall hot legs, four 28" ID, 2.33" nominal wall crossovers, and four 28" ID, 2.33" nominal wall cold legs. Calibration block 40350 (sketch attached) was used for the first interval inspection of this piping.
Two new calibration blocks would be required to comply with this requirement. This would require fabrication of two new piping sections, cladding, heat treatment, and machining the final calibration blocks.
Use of the existing block (40350) would assure that the second interval inspections are directly comparable to these done during the first interval.
4. Alternate Examination:
Calibration block 40350 will be used for all ultrasonic inspection of
ferritic steel reactor coolant piping welds from the OD surface. Reference levels for the inspections will be set as shown on Attach
ment 2.
Implementation Schedule:
This will apply for all ultrasonic inspections of ferritic steel
reactor coolant system piping during the second ten-year interval for Oconee Units 1, 2, and 3.
.666 A./OTE 7
I. RTrIe9lf AOR OLOe X ____ &Z. 70 FoR CL.9D - .04 4..
Z. I/oLe DIR. -3/
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r v S.Wgfr Ttee* PERt 4.. .6PEC4 Ia .L -WARFCeeS M~ SLF IV9eAlIA/ED
II IIII M /Z5 Z.H1J.
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P. ~~ ~ OOAE rJ/LEQ V .S1 SOAQT/WG N.4050
ATTACHMENT 2
ONS-003
Article 5, nonmandatory Appendix A of the 1980 ASME Section V gives criteria for determining the gain adjustment needed when using a flat calibration block for inspection of a convex item with radius of greater than 10 inches. The method involves comparison of the object radius (R) to a calculated critical radius (Rc), which is dependent on transducer diameter, material, and couplant. If the ratio of the R/Rc is greater than 1.0, no gain correction is needed. The following calculations apply to the Oconee RCS piping:
1. Straight Beam Technique
(A) 28" ID pipe (33.5 OD) Transducer - 1/2" diameter, 2.25 mHz Boron Carbide wear face Synthetic Ester Couplant
from Table A-10, Transducer Factor = 23.2 from Figure A-10(a), Rc = 25
R = 16.75 R/Rc - 16.75/25 = 0.67
from Figure A-10 (b), Correction Factor = 3 db
(B) 36" ID pipe (42.0 OD) same transducer and couplant as in 1(A) R = 21 R/Rc = 21/25 = 0.84
from Table A-10, Transducer Factor = 92.9 from Figure A-10(a), Rc = 18
R = 16.75 R/Rc = 16.75/18 = 0.93
from Figure A-10(b), correction factor = 2 db
(B) 36" ID pipe (42.0 OD) Same transducer and couplant as in 2(A) R = 21 R/Rc = 21/18 = 1.16 No correction is required.
Based on the above calculations, the following will apply to all
contact ultrasonic inspections of ferritic steel reactor coolant system piping at Oconee during the second interval:
1. Straight beam examinations will be conducted using a 1/2" diameter, 2.25 mHz transducer. The reference level sensitivity will be set at 3 db above the response from the side drilled holes.
* -2
2. Angle beam examinations will be conducted using a 1" diameter or smaller transducer. The reference level sensitivity will be set at least 3 db above the response from the notches in the block.
DUKE POWER COMPANY OCONEE NUCLEAR STATION - UNITS 1, 2, & 3
REQUEST FOR RELIEF FROM ASME CODE SECTION XI (WITH ADDENDA THROUGH WINTER 1980) INSERVICE INSPECTION REQUIREMENTS
D. 1. Component for Which Exemption Is Requested:
(a) Name and Number:
Ultrasonic Calibration Blocks for use on the Pressurizers and Steam Generators.
(b) Function: Calibration of ultrasonic instruments for volumetric inspection of welds.
(c) ASME Section III Code Class: Class 1 & Class 2
(d) Valve Category: N/A
2. Reference Code Requirement That Has Been Determined To Be Impractical:
ASME Section XI IWA-2232 (a) Refers to ASME Sec. V Article 4. Paragraph T 434.1 requires that calibration blocks be fabricated from a nozzle dropout, prolongation, or material of the same specification, product form and heat treatment as one of the materials being joined.
3. Basis for Requesting Relief:
The Class 1 pressurizer shells and heads are fabricated from A212 Grade B material.
The Class 2 steam generator shells are also fabricated from A212 Grade B material.
This material is no longer available.
The Class 1 steam generator heads are fabricated from SA 302 Grade B material. None of this material is available in the required thickness ( 9 ").
These welds were examined during the preservice inspection and the first ten-year interval using calibration block 40305, 40338, and 40394. Continued use of these blocks would provide for direct comparison to previous inspection data.
4. Alternate Examination:
Calibration block usage during the second ten-year interval at Oconee will be scheduled as follows:
(a) Pressurizer head to shell welds - Block 40394 (b) Steam Generator head to tube sheet - Block 40305 (c) Steam Generator secondary shell - Block 40394 (d) Steam Generator shell to tube sheet - Block 40338 (e) Pressurizer nozzle to head welds - Block 40394 (f) Steam Generator primary nozzle to head welds - Block 40305
This schedule will be used for all applicable inspections at Oconee during the second ten-year interval.
DUKE POWER COMPANY OCONEE NUCLEAR STATION - UNITS 1, 2, & 3
REQUEST FOR RELIEF FROM ASME CODE SECTION XI (WITH ADDENDA THROUGH WINTER 1980) INSERVICE INSPECTION REQUIREMENTS
E. 1. Component for Which Exemption Is Requested:
(a) Name and Number:
Piping between 1RC-4 and 1RC-66 (SYS 50, ISO 47, Unit 1) 2RC-4 and 2RC-66 (SYS 50, ISO 44, Unit 2) 3RC-4 and 3RV-67 (SYS 50, ISO 45, Unit 3)
(b) Function: Pressurizer Relief
(c) ASME Section III Code Class: Class 1
(d) Valve Category: EMO & Relief Valve
2. Reference Code Requirement That Has Been Determined To Be Impractical:
Table IWB-2500-1, Category B-P, Items B15.71
3. Basis for Requesting Relief:
Personnel safety requirements call for valve RC-4 to be closed during reactor coolant system pressure tests. This valve would have to be open to produce hydrostatic test conditions at valve RC-66 (or valve RV-67).
There is one 3" NPS, 0.438" wall weld, and one 2 " NPS, 0.375" wall weld between these two valves.
4. Alternate Examination:
Both welds in each unit will receive a liquid penetrant inspection at or near the end of the inspection interval. This inspection will be done in addition to any other ISI inspections performed on the system.
5. Implementation Schedule:
This inspection will be performed on each unit at or near the end of the second ten-year inspection interval.
32 ASTM Standards
A21 2 -6 5--nigh Tensile strength carbon-5sllcon steel Plates for Bloilers and other Pressure Vessels
Chemical Requirements
Grade A Grade 8 Carbon, max., per cent:
For plates I in. and under in thickness.......0.28......0.31 For plates over I to 2 in., ind., in thickness 0.31 0.33 For plates over 2 to 8 in., inc., in thickness 0.33 0.35
Manganese, max, per cent...................0.90*....
Phosphorus, max., per cent: Flange
0.04 0.04 Firebox 0.035 0.035
Sulphur, max., per cent:
Flange.......................- ...... 0.05......0.05 Firebox 0.05 .0.04 I, 0.04 0.04 Silicon; per cent: Ladle analysis...........................0.15 to....0.15 to
0.30 0.30 (0) when steel Plates are fwniishod uinder this specification to meet the impact requirements of the Specification for Steel Plates for Presure vessels for service at Law Temperatures (ASTM Designatiotn: A 300), the manganese content shall be 0.85 to 1.20 per cent. When specified, the maximum incidental copper content shall be 0.25 per cent. When specified, the stool sAcll be coarse grained having a carburzed aust nit* grain siz, of I to 5 as5 determined in accordance with the Methods for Estimating
Tensile Requirements
Grade A Grade 8
Tensile strength, psi 65,000 to 70,000 to 77,000 85,000
Yield point, min., psi .................. 35,000........38,000
Elongation in 8 in., min., per cent: Flange 20'sIS Firebox 21' 19,
Elongation in 2 in., min., per cent: Flange 23 21 Firebox .............................. 2 4 b ........... 22b
(a) For material .mder Va in thickness deduct 1.25% for each decrease of I/V. Deduct Q.5% for each increase of ts' above 3A' of thickness, not to exceed 3% deduction.
(b) Deduct 0.5% for each increase of Y2' of thickness above 3WA, up to 3% deduction.
Send Diameters
Thick of Ratio of Bond Diameter Mat'l,30 to Thickness of Specimen In Inches
Grade A Grade S I &under ............................. I A ............ 2 Over Ito Y2, incl 2 2 Over 11 2 to 3, incl 2 21/2 Over 3to 4/ 2 ,ind. 21/2 3 Over4b to 8, i.. ... ... ..... 3.............312
oNs-0 04 GadATeACHMENTA
SA-515 SECTION II - MATERIAL SPECIFICA'W S
SUPPLEMENTARY REQUIREMENTS
Supplementary requirements shall not apply unless specified in the order. A list of standardized supplementary requirements for use at the option of the pur
chaser are included in Specification A 20. Those which are considered suitable for use with this specification are listed below by title.
Yield strength minb ksi (MPa) 30.0 (207) 32.0 (221) 35.0(241) 38.0(262) Elongation in 8 in. or 200 23 21 19 17
mm. mina Elongation in 2 in. or 50 27 25 23 21
mm. mina
I See Specification A 20 bDetermined by either the 0.2 percent offset method or the 0.5 percent extension-underload method.
By publication of this standard no position is taken with respect to the validity of any patent rights in
connection therewith, and The American Society of Mechanical Engineers does not undertake to insure
anyone utilizing the standard against liability for infringement of any Letters Patent nor assume any such
liability.
ONS-004 ATIACIMEN 2
616
THE BABCOCK & Willcox COT1.1ARY POWER GENERATION DIVIS!ON
NOTES:
1. ALL SURFACES TO BE PARALLEL WITMIN !.003" 2 TOP & BOTTOM SJRFACES TO HAVE 250 RMS FINISH
3. HOLE DIAMETERS TO 3E .1375" 4. ALL THRJ HOLES J4LESS OTHEP.WISE NOTED. 5. BASE V~ATE:ZIAL TO BE CAR30:1 STEEL (SA-515 GR 60/70) q1: n" _p
6. CLAODIMG TYPE . STAIILESS STEEL .1875" THK.
7. Diara'.Sin*IAL TO'.ppirz is I.01"4 7 -3 rl ~
DIE STA'.P IIFOlMATIO I to/ EITVE AD T
BLOCK 40105 DELETED NOTE 8-AED HOLE
CLAD THICKNESS 3/16' SS 24.75 BASE MATERIAL CS ADDED NOTCH-Y
HOLE DIA. 2/3"
HOLE DEPTH TOP VIEW
TOPSON MacIEt.
"A" 2.63 A6'.DOTC3 'OC
'3" 225-4" 9!
"C' 2.281 "
"S2.078 1U .. D A E S
'E' 2. 250
2.' ' 355 " Z 4
Th__T 2" 2C"57
05
0_ 4 487
8.90"
6 R562' R E CA GO
"A" 2.636A" __
"E" 2.250
*1.443'
ED \ -DIE STAMP TIS END!Z.V.SIDE
oi1 __ __ _ __ _ __ _ __ _i)Ir o P;: . I T :10. 192011 L"T
?w Tzo
DUKE!"I 2 &"
. . Technical Ev uation of Calibration Bl .#A0305
"T" (thickness) as defined by the-Code-includes the cladding. For this block, T = 9.09". The basic 1/4, 1/2, and 3/4T holes
will be based on this dimension.
"T" Location
Hole Actual Required Deviation
1/4T 2.250"- 2.273"- - .023"
1/2T (B)* 4.413" 4.545" ..132"
3/4T (D)* 6.743" 6.818" .075"
The '77 Edition of Section V, Article 4 allows a tolerance of
±1/8 inch for hole locations. The 1/2T (B) hole location is out
of tolerance and is located less in the thickness direction than the required 1/2T position. This does not invalidate the use of the block for calibration purposes. The hole reflectors in a calibration block are used to establish a distance-amplitude correction (DAC) curve which determines the examination sensitivity through the thickness of the component being examined. The 1/4, -1/2, and 3/4T hole locations are minimum requirements selected on the basis
of uniformity in the thickness direction. Additional hole .reflectors are allowed and can be used to more accurately define the DAC curve.
Holes identified as "A" and "C" are of these type and the range over
which the DAC is established exceeds that which would be established if only the 1/4, 1/2, and 3/4T holes were used.
The location of the holes from the ends of the block are not con
sistent with the Code requirements, however, an ASME interpretation exists which states that this dimension need not be complied with
if the proximities do -not influence the calibration. This is the
case with this block.
The Code recuires that the hole diameter.be 0.375" for this block
thickness; each of the holes should be drilled -to this diameter for
a depth of 3 inches.
To establish the sensitivity for surface planar flaws at the opposite
surface, a notch would have to be added to the block. This should
be located directly below hole "D" and extend through the clad 2%T
into the base metal.
*The letters correspond to those shown on drawing #PC-24604-6.
