ML20046A753
| ML20046A753 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/22/1993 |
| From: | Hodges M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| References | |
| NUDOCS 9307300013 | |
| Download: ML20046A753 (2) | |
See also: IR 05000317/1993008
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JUL 2 21993
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Docket Nos. 50-317
50-318
Mr. Robert E. Denton
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Vice President - Nuclear Energy
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Baltimore Gas and Electric Company
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Calvert Cliffs Nuclear Power Plant
1650 Calvert Cliffs Parkway
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Lusby, Maryland 20657 - 4702
Dear Mr. Denton:
SUBJECT: COMBINED INSPECTION NOS. 50-317/93-08 AND 50-318/93-08
This refers to your June 1,1993, correspondence, in response to our April 23,1993, letter.
Your letter of June 1,1993, in response to the Notice of Violation transmitted with NRC
Inspection Report No. 50-318/93-08 informed us that you disagree with the violation.
We have reviewed the reasons for disagreement stated in your letter and we feel that they are
not pertinent to the circumstances leading to the violation. The violation is based on the fact
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that the rejectable indications were accepted by Baltimore Gas and Electric Company.without -
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characterizing the indications as required by the Code. Separate and distinct, but relevant is
the fact that we do not believe the ultrasonic technique employed for characterizing the
indications is capable of detecting and sizing near surface MT identified cracking. For these
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reasons, we still consider it to be a valid violation.
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Your cooperation with us is appreciated.
Sincerely,
Marvin W. Hodges, Director
Division of Reactor Safety
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.9307300013 930722-
0FFICIAL RECORD COPY G:RLCC.Rf1
ADOCK 05000317
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UL 2 21993
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Mr. Robert E. Denton
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cc:
G. Detter, Director, Nuclear Regulatory Matters (CCNPP) '
R. McLean, Administrator, Nuclear Evaluations
J. Walter, Engineering Division, Public Service Commission of Maryland
K. Burger, Esquire, Maryland People's Counsel
R. Ochs, Maryland Safe Energy Coalition
K. Abraham, PAO (2) (w/ copy of letter dtd June 1,1993)
Public Document Room (PDR)
Local Public Document Room (LPDR)
Nuclear Safety Information Center (NSIC)
NRC Resident Inspector _.(w/ copy of letter dtd June 1,1993)
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State of Maryland (2) (w/ copy of letter dtd June 1,1993)
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Region I Docket Room (with concurrences)
bec (VIA F MAIL):
V. McCree, OEDO
R. Capra, NRR
D. Mcdonald, NRR
J. Durr, DRS
H. Gray, DRS
R. McBrearty, DRS
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OFFICIAL RECORD COPY G:RLCC.RM
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BALTIMORE
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GAS AND !
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1650 CALVERT CUFFS PARKWAY . LUSBY, MARYLAND 20657-4702
ROBERT E. DENTON
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VsCE PRESIDENT
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NUCLEAR ENERQY
(410) 260-44S5
June 1,1993
U. S. Nuclear Regulatory Commission
Washington, DC 20555
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ATTENTION:
Document Control Desk
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SUBJECT:
Calvert Cliffs Nuclear Power Plant
Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318
Non-destructive Examination Notice of Violation
REFERENCE: (a)
Letter from Mr. J. P. Durr (NRC) to Mr. R. E. Denton (BG&E),
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dated April 23, 1993, NRC Region I Inspection of Calvert Cliffs
Units 1 and 2 Inservice Inspection Activities, Combined Inspection
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Report Nos. 50-317/93-08 and 50-318/93-08
Gentlemen:
In response to Reference (a), Attachtnent (1) is provided. Basci on the information contained in
this attachment, we ask that you reconsider the v.slation.
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Should you have any further questions regarding this matter, we will be pleased to discuss them with
you.
Very truly yours,
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RED /DWM/dwmsbjd/rej
Attachment
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Document Control Desk
. June 1,'1993
Page 2
cc:
D. A. Brune, Esquire
J. E. Silberg, Esquire
R. A. Capra, NRC
D. G. Mcdonald, Jr., NRC
T. T. Martin, NRC
P. R. Wilson, NRC
R. I. McLean, DNR
J. H. Walter, PSC
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A'ITACIIMENT (1)
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NOTICE OF VIOIATION 50-318/93-08-01
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Notice of Violation 50-318/93-08-01 states that contrary to Technical Specification (TS) 4.0.5, which
requires Inservice Inspection (ISI) of ASME Code Class 1,2, and 3 components to be performed in
accordance with Section XI of the ASME Boiler and Pressure Vessel Code, rejectable magnetic
particle indications on main steam system welds 34-MS-2001-6 and 36-MS-2001-3 were examined and
accepted using an ultrasonic examination method that failed to establish the dimensions of the flaws
as required by ASME Section XI.
Baltimore Gas and Electric Company disagrees with this violation. Our understanding of the Code is
that the purpose of determining the dimensions ofindications is to determine whether they are or are
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not of sufficient size to be rejectable. Once this determination is made, further dimensioning of
indications is unnecessary. We believe that the technique used in this case was . sufficient to verify
that the indications found were not of sufficient size to be rejectable. We have asked the Electric
Power Research Institute's (EPRI's) Non-destructive Examination (NDE) Center to verify that this
is in fact the case. We have also written to the ASME Code Committee requesting an interpretation
regarding our use of the technique.
On March 2,1993, we discovered, via magnetic particle examination, a 3/8" linear indication on weld
3 of the main steam line (36-MS-2001). On the same day, a similar indication was found on weld 6 of
the same line. Both flaws were rejectable due to their length per ASME Code Section XI, IWB-
3514.7 and Table IWB-3514.4. On March 3,1993 we performed an Ultrasonic Examination of both ,
welds per ASME Code Section XI, IWB-3514.2(b). The method used was a 45 degree full vec shear f
wave described in Appendix III of the Code. The Ultrasonic Examination failed to find any -
indications in either weld. The location and orientation of the surface indications were known and
accounted for during performance of the examination. We documented our conclusion that since {
the flaws were not deep enough to be detected by ultrasonic examination, they could not be deep i
enough to be rejectable. Given the calibration sensitivity and pipe size we were examining, a 14.6
percent throughwall crack would have been acceptable. We therefore accepted the welds.
We believe that the 45 degree full vee shear wave technique we used is capable of identifying
rejectable indications initiating at the OD surface of a pipe in accordance with IWA-2232(b) and
IWB-3514.2(b) of the Code. This is the. standard technique used by our vendor to detect reflectors in
ferritic piping. The examiner calibrated using 10 percent throughwall deep notches and increased
the sensitivity of the instrument by increasing the gain 6.14, and 20 decibels (2,5, and 10 times the
reference level sensitivity) during the course of the examination. He verified that sound was getting
to the surface by creating a couplant pocket and obtaining a reflector. He received no recordable
indications even with significantly increased instrument sensitivity and concluded that the indications
had no measurable throughwall dimension. The indications would have to be detectable and
therefore measurable in order to be rejectable. The technique would have detected a 14.6 percent
throughwall crack. Had a measurable throughwall indication been found we would have sized the
indication.
Our conclusion was confirmed when we examined the area containing the surface flaws using a high
angle ultrasonic sizing technique advocated in the subject inspection report as being appropriate.
We obtained exactly the same results from this examination (no detectable throughwall indications)
as we had from the earlier one. We believe that the earlier technique found no indications because
there were no throughwall indications to find, rather than because it is not an appropriate technique.
We have requested that the EPRI NDE Center verify this conclusion by demonstrating the ability of
the technique to detect throughwallincications in circumstances similar to ours.
The subject inspection report discusses a demonstration at another utility in which the technique
failed to identify five out of seven cracks emanating from the OD surface of a pipe We have
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ATTACI! MENT (1)
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NOTICE OF VIDIATION 50-318!93-08-01
discussed this with the utility in question and believe that the findings of this demonstration are not
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applicable to our situation. The demonstration involved a blind test of a section of stainless steel
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pipe for an unknown number of indications of unknown size or orientation. We were looking for a
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previously located indication of known orientation in a carbon steel pipe. It is more difficult to locate
surface flaws in stainless steel than carbon steel. The unknown indications in the demonstration
were located on the weld surface and toe of the weld while the indications we were examining were
both located on the base metal, where flaws are more easily located. None of the demonstration
indications were greater than five percent throughwall and the test found 40 percent of them.
Although we believe that the technique used was acceptable, we will use techniques to more exactly
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size indications until such time as we receive answers from the Code Committee and EPRI, at which
time we will make any appropriate program changes.
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