ML20238E920
| ML20238E920 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/31/1997 |
| From: | Minor C GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20238E914 | List: |
| References | |
| RTR-REGGD-01.150, RTR-REGGD-1.150 NUDOCS 9809020298 | |
| Download: ML20238E920 (8) | |
Text
v' - '- - - - - - --
-3 i
l GE Nuclear Energy
. - <- - _ a,w.
Attachment 2-to hts 980133 7 Pages Total GERIS 2000 INVESSEL SYSTEM ALTERNATE METilOD FOR COMPLIANCE TO REGULATORY GUIDE 1.150 March 1997 l>repared Ily: Chris A. Minor NDE Specialist, GENE. Inspection Services i
l i
1 i
l 1
1 9809020298 980831 PDR ADOCK 05000298 G PDR i
GE Nuclear Energy
. a - m,.
INTRODUCTION l
Reactor vessels must periodically be volumetrically examined according to Section XI of the ASME Code. l The rules of Section XI require a program of examinations, testing, and inspections to evidence adequate l safety. To ensure the continued structural integrity of reactor vessels, it is essential that Oaws be reliably j detected and evaluated. I During the mid 1970's, the USNRC became concerned with the adequacy of ASME Section XI examinations performed on Reactor Pressure Vessel (RPV) assembly welds. These concerns were well founded, since the examinations being performed were not consistent, j 1
The USNRC did a study of NDE methods, procedures, and ASME Section XI, PSI / ISI data. The results ;
of this study showed that some standardization of methods and recording criteria was required. In July of 1981, Regulatory Guide 1.150 (RG 1.150) was issued. Revision I of this Regulatory Guide, which allowed approved alternate methods of compliance, was issued in 1983. General Electric has been complying with Revision 1, using the alternate method, since then.
l RG 1.150 provided a much needed first step in the continuing improvements of RPV assembly weld l examination techniques. These improved techniques, along with changes in the ASME Code, have l rendered parts of the Regulatory Guide obsolete.
Later Editions and Addenda to the Code have attempted to address the evident short comings of the l volumetric examinations specified for reactor pressure vessels. The most comprehensive attempt to improve the reliability of examinations has been Appendix Vill, ASME Section XI which requires that procedures, equipment, and personnel who detect or size flaws be qualified by performance demonstration.
1 in November of 1994 General Electric successfully completed a performance demonstration of the GERIS
)
2000 invessel system administered by representatives of the Performance Demonstration initiative (PDI). i The performance demonstrations were in accordance with the PDI-RPV Protocol document implementing the requirements of Appendix Vlli, ASME Section XI,1992 Edition with the 1993 Addenda.
General Electric's previous experience with RPV performance demonstrations using implanted Daws indicated that examination procedures based on Article 4, ASME Section V methods were not capable of reliably detecting or sizing flaws with the degree of accuracy required for an Appendix Vlli demonstration.
Due to this experience the examination and sizing procedures submitted for performance demonstration specifically did not comply with the requirements of Article 4. The procedures were written to incorporate the lessons learned from industry experiences with IGSCC, weld overlay examinations and RPV sample specimens w here actual flaws directed technique development.
As RG 1.150 was written to standardize examinations based on Article 4, General Electric's qualified procedure does not comply with many ofits requirements. General Electric's position is that the qualified procedures meet the intent of RG l.150 by providing an examination that significantly increases the probability that flaws be reliably detected and evaluated.
This paper is intended to itemize those areas u here the qualified procedure does not comply with RG 1.150 and General Electric's basis for non-compliance.
. , . . 2 . . . , , -
GE Nuclear Energy
- - c . - c..
1.0 INSPECTION SYSTEM PERFORM ANCE CllECKS The performance checks specified are not performed as part of the qualified procedure.
. The checks specified are required to document the performance characteristics of the inspection system for the purpose of comparison of examination results. The performance characteristics of an ultrasonic system I are determined by the system's electronics and search unit parameters.
Appendix Vill defines the system electronics i.e., pulsers, receivers, cables and search unit parameters as
" essential variables" and permits the substitution of these essential variables only under strictly limited conditions.
A comparison of the subject equipment's ability to detect and size flaws under controlled conditions provides a better means for the comparison of examination results.
1.1 Pre-exam Performance Checks l- a. The design of the GERIS 2000 does not provide any pulse shape or noise suppression controls.
l l b. RF Waveform l
. RF Waveforms from reference reDectors are not obtained as part of the qualified procedure.
' The GERIS 2000 records every RF waveform for each search unit position during the examination. This data is available and can be processed to obtain the frequency amplitude information at the time of Haw detection.
1.2 Field Performance Checks i
- a. The design of the GERIS 2000 does not provide any pulse shape or noise suppression controls.
- b. Instrument Sensitivity during Linearity Checks The GERIS 2000's sensitivity is not dependent on any gain settings normally available to the system's
, operator. Due to the design characteristics of the GERIS 2000 the linearity checks specified by the Code do not verify any portion of the ultrasonic system's electronics or displays.
- c. RF Waveform RF Waveforms from reference reDectors are not obtained as part of the qualified procedure.
!- The GERIS 2000 records esery RF waveform for each search unit position during the examination. This data is available and can be processed to obtain the frequency amplitude information at the time of Haw detection.
- d. Screen lleight Linearity Due to the design characteristics of the GERIS 2000 the screen height linearity checks specified by the l , Code do not veiify any portion of the ultrasonic system's electronics or displays. j
- . . 3 ..-
l 1
. 1 1
GE Nuclear Energy
< . e m m , ,.
i 1
- e. Amplitude Control Linearity Due to the design characteristics of the GERIS 2000 the amplitude control linearity checks specified by the Code do not verify any portion of the ultrasonic system's electronics or displays.
- f. Angle lleam Profile Characterization lleam profile measurements are not obtained as part of the qualified procedure. ;
Angle beam profile data is required for amplitude based sizing techniques using beam spread correction.
Amplitude based sizing is not used by the GERIS 2000 invessel system.
The flaw sizing methods used by the GERIS 2000 Invessel system are tip diffraction based and have been qualified by performance demonstration. l
- 2. cal,lilRATION l l
Ultrasonic calibrations are performed on the GERIS 2000 invessel system only for the purpose of providing a reference Ibr comparison of detected flaws with previous and future data.
The establishment of the DAC curve and sweep calibration complies with Article 4,Section V and Appendix 1 of Section XI.
1 The ultrasonic calibration is performed using the Code calibration blocks specified in the Owners examination plan, both prior to and after a series of examinations.
2.2 Calibration for Mechanized Scanning
- a. Not applicable.
I
- b. Not applicable. l
- c. Not applicable.
- d. The ultrasonic calibrations are perfbrmed statically and a comparison of static versus dynamic performance has been perfbrmed. No correction factor was indicated.
]
2.3 Calibration Confirmation 1
i The GERIS 2000 does not rely on any characteristic of the basic calibration block for flaw detection or sizing and as such no intermediate calibration verifications are performed. i t
Electronic simulators are not used Ibr calibration confirmation.
i 2.4 Calibration Illocks l
The ultrasonic calibration is performed using the Code calibration blocks specified in the Owners !
examination plan. These blocks should comply with the requirements of Appendix 1,Section XI or Anicle 4,Section V as applicable..
,,...,.. 4 ~
GE Nuclear Energy i- -., ~ .,c o r.
- 3. EX AMINATION The scope and extent of ultrasonic examinations compl 3 with IWa-2000,Section XI.
The gates specified by the qualified procedure include the entire thickness of the required examination volume.
The scan overlap specilled by the qualified procedure is greater than the minimum 25 percent requirement.
3.1 Internal Surface The GERIS 2000 invenci system has successfully demonstrated the ability to detect, length size and thruwall size flaws located at the clad / base material interface (Supplement 4 ).
- a. Not applicable.
- b. The qualified pro;edure does not rely on any characteristic of the basic calibration block for flaw detection or sizing and the use of an alternate reflector is not indicated.
- c. The qualified procedure effectively examines the entire thickness of the required examination volume.
3.2 Scanning Weld-Metal Interface The GERIS 2000 invessel system has successfully demonstrated the ability to detect, length size and thruwall size flaws located in the base material other than at the clad / base material interface (Supplement !
6). This demonstration included unfavorably oriented planar flaws i.e. oriented perpendicular to the I examination surface.
- 4. IIEAM PROFILE (DELETED)
- 5. SCANNING WELD-METAL INTERFACE (DELETED)
- 6. RECORDING AND Sl7.ING The GERIS 2000 invessel system has successfully demonstrated the ability to detect, length size and thruwall size flaw s to the requirements of ASME Appendix Vill, Supplements 4 ar'd 6.
These demonstrations were administered in November of 1994 by representatives of the PDI. The performance demonstrations were in accordance with the PDl-RPV Protocol document implementing the requirements of ASME Section XI, Appendix Vill,1992 Edition with the 1993 Addenda.
The demonstrated recording and sizing techniques are those used for examination.
6.1 Geometric Indications Geometric indications are recorded and the nature of the geometry is described.
I
- . . s . , , .
l
l.
, GE Nuclear Energy c - ~ .c -.
. 6.2 indications with Changing Metal Path I a. All indications with apparent thruwall dimensions are recorded regardless of amplitude.
l
- b. All relevant indications exceeding 50% of DAC are recorded and characterized using demonstrated
' techniques.
- c. All relevant indications exceeding 20% of DAC are recorded and characterized using demonstrated l techniques.
' 6.3 Indications without Changing Metal Path
- a. All relevant indications are recorded and characterized using demonstrated techniques i
. ; b. All relevant indications are recorded and characterized using demonstrated techniques
- c. The GERIS 2000 displays are not subject to this effect 6.4 Additional Recording Criteria I
- a. Indications are recorded every 0.25 inch.
- b. Indication metal path and search unit position is recorded at 20%,50% and 100% DAC and at the maximum amplitude of the signal. This information is for reference only and is not utilized for flaw sizing.
. c. The GERIS 2000 Invessel system does not use the automated detection and recording system described in this paragraph.
- 7. REPORTING OF RESUlsTS The Final Report documenting the examinations performed by the GERIS 2000 invessel system is provided to the Owner. Maintenance of this document is the Owners responsibility.
l Relevant indications sized by the demonstrated Gaw sizing techniques are characterized in accordance with the rules ofIWA-3000 and evaluated to the acceptance standards of IWB-3000. Indications exceeding the acceptance standards of IWB-3000 are reported to the Owner. The Owner is responsible for the final disposition and subsequent reporting of these indications.
- a. The Dave sizing procedure has successfully completed a performance demonstration in accordance with ASME Section XI, Appendix Vill, Supplements 4 and 6 as implemented by the PDI.
The flaw sizing tolerances are within the acceptance criteria of Appendix Vill as implemented by the PDI.
The actual error band established by the performance demonstration is not currently available to General Electric. This information is available on request by PDI member utilities and the USNRC from the PDl.
j b. The examination procedure has successfully completed a performance demonstration in accordance with ASME Section XI, Appendix Vill, Supplements 4 and 6 as implemented by the PDI.
} c. This estimate and supporting drawings or descriptions are provided to the Owner as pan of the Final Report documenting the examination.
is utu mt 6 me, i s >c
- L__-_____-_____-__-_-_-___-_____________ _ _ _ - - - - .
GE Nuclear Energy
.-~~cm._,m,.,,.
- d. These drawings are provided to the Owner as part of the Final Report documenting the examination.
I
- e. Not applicable.
l
)
\
l l
l l
1 i
. . . . . . 7 . ,u.*
a l ATTACHMENT 3 LIST OF NRC COMMITMENTS l
)
Correspondence No: NLS900133 The following table identifies those actions committed to by the District in this document. Any other actions discussed in the submittal represent intended or planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the NL&S Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.
COMMITTED DATE COMMITMENT OR OUTAGE Refueling Outage 18 The automated RPV shell weld and shell to flange weld and, as necessary, examinations shall be performed using PDI examination during the remaining techniques in accordance with ASME Section XI, Appendix p rtion of the Third VIII, 1992 Edition, 1993 Addenda in lieu of, or in te al, addition to ASME Section XI, 1989 examination techniques,
- n ; ngen up gg approval. ,
l l
1 i
l l
i l
l PROCEDURE NUMBER 0.42 l REVISION NUMBER 6 l PAGE 9 OF 13 l
_ _ _ - - - - _-