ML14175B485
| ML14175B485 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 08/24/1987 |
| From: | Herdt A NRC Office of Inspection & Enforcement (IE Region II) |
| To: | Utley E Carolina Power & Light Co |
| References | |
| NUDOCS 8708280056 | |
| Download: ML14175B485 (3) | |
See also: IR 05000261/1987007
Text
AUG 2 4 1987
Carolina Power and Light Company
LAT-N:
Mr. E. E. Utley
-Senior Executive Vice President
Power Supply and Engineering
and Construction
P. 0. Box 1551
Raleigh, NC
27602
Gentlemen:
SUBJECT:
REPORT NO. 50-261/87-07
Thank you for your response(s) of July 14,
1987, to our Notice of Violation
issued on June 19,
1987,
concerning activities conducted at your Robinson
facility.
We
have evaluated your response and found that, for the reasons
stated in the Attachment to this letter, your response does not meet the
requirements of 10 CFR 2.201.
Therefore, pursuant to the provisions of 10 CFR
2.201, Carolina Power and Light is hereby required to submit to this office
within 30 days of the date of this letter an amended response to the Notice of
Violation, dated June 19, 1987.
We appreciate your cooperation in this matter.
Sincerely,
Qn
- gth
BY
ALAN R. EWT
Alan R. Herdt, Chief
Engineering Branch
Division of Reactor Safety
Enclosure:
Reason for Amended Response
cc w/encl:
LG- P. Beatty, Jr., Vice President
Robinson Nuclear Project Department
LR
E. Morgan, Plant General Manager
bcc w/encl:
tRC Resident Inspector
Document Control Desk
State of North Carolina
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8708290056 870824
ADOCK 05000261
ENCLOSURE
REASON FOR AMENDED RESPONSE
Technical Evaluation of Carolina Power and Light Response Serial RNPD/87-3180
Dated July 14, 1987.
While the CP&L response acknowledges the violation, the acknowledge reason for
the violation and the corrective actions described in the response do not
reflect an understanding of the technical issues or the significance of the
violation.
The first issue which must be understood is that there are two different
methods for ultrasonic examination of piping welds recognized by the ASME code.
One method requires the examination and evaluation of the entire volume of weld
and pipe base material; and the calibration block for this examination contains
side drilled holes. (This is the calibration block that is addressed in ASME
Code Case N-98). The second method requires that the examination focus on the
inner one third of the volume of weld and pipe material; and the calibration
block for this examination contains notches on the I.D. and 0.D. surfaces.
The examination utilizing the side drilled hole calibration block is a more
sensitive examination because the side drilled hole is a poorer reflector of
the ultrasound than the notches. The code case N-98 tolerances on calibration
block thickness can be applied because the entire volume of material must be
evaluated.
The examination utilizing the notch reflectors trades examination sensitivity
for other factors which include the fact that a surface notch more nearly
simulates the type of reflection which would be expected of a crack, and the
fact that the ID notch almost exactly simulates the location of an expected
crack.
Because of the additional consideration that a crack will not reflect as strong
a signal as the calibration notch, it is very important that the examiner be
very sure where to expect to see crack-like indications during inspections that
use a notched calibration block. This is only possible if the examiner is sure
that his calibration block is the same thickness as the item to be examined.
The second issue that must be understood is that code case N-98 is very
specific in its application to a calibration block which contains side drilled
holes. The use of this code case for any other application cannot be autho
rized by the Authorized Nuclear Inservice Inspector (ANII)
or by a code
inquiry. A*deviation of this type would have to be authorized by another code
case (which would have to be approved by NRC prior to use) or by a relief
request submitted to NRC.
Based on the discussion above and review of the CP&L response, it appears that
the following questions remain unanswered:
Reason for Amended Response
2
1. The response states that the footnote stating eight inch (8") Schedule 120
was to "Accommodate
Possible Redesign of the piping by future plant
modification".
Question:
How did "Possible Redesign"
information get put on working
inservice inspection isometric drawings?
2. The response states that the footnote of the sketch was not the basis for
block selection.
Questions:
A. Who was responsible for selecting the calibration
block for the examination?
B. What was the basis for the selection?
C.
How was the information concerning what calibration
block to use transmitted to the examiner?
3. The response states that the sketch was referred to only for other piping
information.
Question:
A.
What other piping information from the sketch was used
during the examination?
B. Based on the Validity of the 8" Schedule 120 note,
what has been done to verify the validity of other
piping information on the sketches?
4.
The response lists corrective actions which have been taken and which will
be taken. These corrective actions involve the subject drawings but do
not address
the validity of inspections conducted using the wrong
calibration block.
Question:
A.
How many welds were inspected using the wrong
calibration block?
B. When will nonconforming inspections be repeated?