ML20203K172
Text
r a.
.fqT[k'.
- v UNITED STATES
' ///, * ]pg ATOMIC ENERGY COMNISSION 7 L.
?.
i g,.g DIRECTORATE OF REGULATORY OPERATIONS a
230 PE AcHf mEE St AEET. HOpiHWEST
'.-//G.
y nEoic,,, se - suit e ein g y;iT,.,
'1 S
f4re O AT 4. A M7 A, oEo84Gi A 30303 g,,,,,J4,,S,,
[
.,)
In Reply Refer To:
FEB 151973 50-259, 50-260
. > p h.
,h 7) '*"J '
RO II:FJL f
(
50-296 0./
- ( C I.'- - [l.' d I
l t'. 6 (
l t
i Tennessee Valley Authority Atta: Mr. J. E. Watson Manager of Power 818 Power Building Chattanooga, Tennessee 37401 Gentlemen:
This letter provides additional information regarding AEC requirements on the subject of verification of the wall thicknesses of valves I
inportant to nuclear safety brought to your attention in our letter of June 30, 1972. We have completed our evaluation of your letters
' ' dated September 29, 1972, and December.1, 1972, in response to our June 30, 1972, letter. The Regulatory', Operations position on vclve thickness verification has been further clarified and is as stated in the enclosure to this letter.
,,., egj In view of the additional information contained in the enclosure, you uny find it necessary to readjust your program for verification of valve wall thicknesses.
Regulatory Operations inspectors will examine your
~
l verification program and the documentation of results against the pre-viously established requirements and the enclosed additional information on subsequent inspections of the above docketed facilities.
Should you have any questions regarding this letter, you may com:nunicate directly with this office.
I Very truly yours, 8604300329 860317 PDR r)b.e PDR FOIA MORROWOS-702
/ John G. D&Yis l
b Director asc---",
Enclosure:
l CFP.TT As stated FEB 231973 v
OFFitt of THE y ' GIMMER OF I4MR q
J,
s*
s
=
ENCLOSURE DOCKET NOS.
50-259, 50-260 50-296 i
VALVE WALL THICICIESS VERIFICATION PROGRAMS Subsequent to issuance of Regulatory Operations Region II letter of June 30, 1972, requesting submittal of plans for verification of certain valve wall thicknesses, some responses contained deviations from the AEC requirements contained in the June 30, 1972, letter. The following additional information clarifying the AEC position will be utilized by Region II in evaluation of verification programs and results:
1.
Valve Sizes All valves, cast and forged, of sizes listed for PWR's and BWR's in the June 30, 1972, letters to licensees are to be included in the licensees' valve verification program, unless specific exceptions are permitted by Items 3, 4, and 5 below.
2.
Acceptable Measurement Techniques and Accuracy Any measure ~ent technique may be used for acceptance purposes, m
providing it can be shown to yield meaningful valve wall thickness measurements.
Realizing that 2% maximum error in repeatability and accuracy is a stated goni, a lower level of measurement accuracy than 2% is per-mitted for acceptance purposes, provided the measured wall thickness value shown by the particular techn'ique exceeds the required thickness by an amount sufficient to cover the maximum measuremeat error. The use of measurement techniques having less accuracy than 2% carries with it the possibility that the valve walls may have to be thicker (greater than 2%) than the design value to be acceptable.
3.
Conditional Acceptance a.
Forged Valves Forged valves which may not require verification are those whose design is such (as may be shown by valve drawings) that any internal machining operation could not have encro~ ached upon the minimum wall thickness of the pressure-retaining boundary of the valve body.
O -
'o 1
2 '.
v b.
Forged Valves 2-1/2 Inches and Le'ss i
Forged valves 2-1/2 inches and less that are mass-produced from.
standardized forging patterns may not require verification, pro-l
' vided that the manufacturing process QC requires periodic checks of the final machining process, and which have been shown by documented audits (by the buyer or his representative) to satisfactorily control tha Jimensional requirements of the valve design.
I
- 4. ' Valve Verification Alternatives Regulatory Operations will consider alternative methods of valve verification in situations where full compliance with the require-ments of our letters would result in hardships or unusual difficulties without a compensating increase in the assurance of system integrity.
Proposed alternative methods of valve verification must provide an acceptable level of assurance that system integrity will be maintained.
l Licensees requesting such consideration should submit a detailed repcrt to the Regulatory Operations Region II Of fice, discussing the specialized nature of each problem and providing sufficient supporting information on proposed alternative verification methods to permit an AEC evaluation.
l 5.
Valve Acceptance Through Evaluation or Special Testing 6,
Licensees planning to utilize valves having less than the design minimum wall thickness (and which are not acceptabic to the terms of the June 30, 1972, letter) and whc intend to justify the use via enginecring calculations, special tests or chanae of operating conditions, should submit to the Regulatory Operations Region II Office a detailed engineering evaluation, the results of any special testing, or such other engineering documentation as the situation may require.
The information to be submitted by the licensee must provide sufficient engineering detail to permit a thorough technical review of each specific application.
(Multiple cases may be grouped, if appropriate.)
t 4
I t
1 w
y l
0 h
,.. - ~.
m u so..o
'U1HTED STATES GOVERNMENT CMO7dndMM TENNESSEE VALLEY AUTHORITY TO D. B. Weaver, Chie Mephanical r
fechanical Design Branch, 204 UB, Knoxville FROM R. '. Hathcote, Pro et ager, Browns Ferry nuclear Plant, Decatur DATE May 23, 1973
SUBJECT:
EROWNS FERRY NUCLEAR PLANT - ULTRASONIC THICKNESS MEASURH4ENTS OF UNIT 1 VALVES Equipment selection for ultrasonic thickness measurements of valves was made by Browns Ferry personnel en December 4, 1972.
seesuse of its accuracy, the Krau.tkramer ultrasonic D-meter.was selected over other available it.struments. Grain structure and thickness of the valves -to be tested required the use of the KMS-2 (2MHz,1" diameter) probe and a KMR-4 (LMH 1/2" diameter) probe.
zs Material with the same "P" number (as identified in ASME code, section IX, paragraph Q-ll.1 or QN-ll.1) as the valves to be measured was obtained from available vendors and shipped to Browns Ferry for machining jnto step wedge calibration blocks. After the machinin6 process, each step
, of each block was measured with micrometers (which were calibrated to
- standard gage blocks) a minimum of th:ee times, and the average thick-ness was permanently stenciled on each step. To assure each block was comparable to the valves to be tested, a ecmparison test was made of each block to measurements on uninstalled valves. At this time,.both the IC43-2 and the KMR-4 probes were tested for accuracy on curved sar.
faces by calibrating on each block and then checkin6 for accuracy and repetition on a curved surface with a radius equal to or less than the valves to be measured. Both probes were evaluated and found satisfactory.
Glycerine and Krautkramer pacte, the couplants selected for use in the test, were compared en each step of each calibration block. The couplants were deemed co= parable iith a maximum deviation of.003" at over 2 500".
After verification of test equipment and calibration references, Browns Ferry NDT personnel (certified ASNT-TC-1A Level II, certifications attached) performed the inspection of unit 1 valves which was completed on May 1, 1973 All calibration data was performed in accordance with Browns Ferry construction procedure EF-57 (copies attached). All measuremento taken were cubmitted to DED pc.rsonngl for verification and acceptance. As a redundant measure to assure all required valves were checked, a detail study of TVA drawing 47W817-1, flow diagram (attached),
was made, and all valves measured were properly marked on the drawing.
Review of the complete cystems shows all required valves were measured.
II R. T. Hathcote
(
/ KAH:MW Attachments:
See page 2 5
Buy U.S. Savings Bonds Regularly on the Payroll Savings Plan
Q.'
- ~
7
- L 2
D. B. Weaver v
May 23, 1973 BROWNS FERRY NUCLEAR PLANT -_ ULTRASONIC THICKNESS MEASURE 4ENTS OF UNIT 1 VALVES Attachments:
1.
Comparison of Ultrasonic Thickness Gac6e8 2.
Information en Krautkramer D-Meter 3
Conversion Table for D-Meter h.
Receiving Information on Calibration Material 5
Pictures of Calibration Blocks 6.
Drawings of Calibration Blocks 7
Certification of Standard Gage Blocks 8.
BF-57 Attact=ents 9
Certifications of NDT Persor,nel 10.
TVA Drawing 47W817-1, Flow Ipagram cc-M. N. Bressler, 213 UBA, Knoxville
\\
8 B. A. Gant, Browns Ferry R. L. Harris, 217 UBA, Knoxville M. M. Price, Browns Ferry 1
J. T. Walker, Browns Ferry D
e e
e 4
e e