ML20151N729
| ML20151N729 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 04/14/1988 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8804260002 | |
| Download: ML20151N729 (3) | |
Text
.
'\\
+
DuxE POWER GOMPANY P.O. DOX 33189 (f
CHARLOTTE. N.C. 28949 if RALB. TUCKER m.trWoww-t' m resemast '
(704) syg4Mg stessa,conostr.on April 14, 1988-i 4
b U. S. Nuclear Regulatory Commission
+
Attention: Document Control Desk
. Washington, D. C. 20555 l
Sub,1cet :
RII/WC i
Catawba Nuclear Station Dockot Nos. 50-413 and 50-414 e
IE Report 50-413,-414/88-09
Dear Sir:
Pleash find attached a response to the Violation 414/88-09-01 which was L
identified in the subject Inspection Report.
7Very truly yours, i
IC I
CC ed d
t Hal B. Tucker LTB/6024/sbn j
f Attachments xc:
Dr. J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Conunission Region II
. 101 Marietta Street, NW, Suite 2900
[
t Atlanta, Georgia 30323 Mr. P. K. Van Doorn i
NRC Resident Inspector l
Catawba Nuclear Station SE \\
\\
\\ (\\
8804260002 880414 PDR ADOCK 05000413 A
E
\\
Duke Power Company Reply to Notice of Violation 50-414/88-09-01 10 CPR Part 50, Appendix R, Criterion IX, as iq,lemented by paragraph 17.2.9 of Duke Power Company Topical Report Duke-l requires ths.t measures be established to assure that special processes including nondestructive testing are controlled and accomplished in accordance with applicable criteria.
Technical Specification 3/4.4.5 and Surveillance Requirements 4.4.5.0 require that each generator be determined operable prior to increasing Tavg above 200* F by performing the required Eddy Current (ET) inspection and plugging all tubes that show wall degradation 2 40%.
Contrary to the above, in August 1937, measures to control and accomplish i
nondestructive testing (ET of steam generator tubes) were inadequate in that ET data for two steam generator tubes (one in A generator and one in D generator) were accepted when, in fact, the data showed both tubon met the plugging criteria (1 40% wall degradation). This violation resulted in a violation of Technical 1
Specification 3/4.4.5 in that the plant was operated from August 1987 until December 1987, with two steam generator tubes that should have been plugged.
Response
(1) Admission or Denial of Violation Duke Power Company admits the violation. 11owever, as stated it implies a lack of "measures to control and accomplish nondestructive testing". Two personnel errors were made in the interpretation of eddy current test data l
for S/G's A and D in August 1987. These errors in no way indicate a lack of "measures to control and accomplish nondestructive testing". The violation of T/S 3/4.4.5 was reported in Licensee Event Report 414/88-02.
(2) Reasons for Violation of Technical Specification 3/4.4.5 l
The applicable criteria for eddy current inspections at Catawba is found in Technical Specification 3/4.4.5 and Duke Nuclear Guide 1.83.
Procedures l
ISI-460 and ISI-464 uare written to control the analysis of eddy current inspection data.
These procedures require a documented review of data.
l The NRC has not identified any regulatory requirement requiring a second evaluation of eddy current data. The NRC stated in IE Report 50-413/87-38 and 50-414/87-38 that "although there is not a requirement to conduct a second evaluation of the data, that the economical consequences associated with a missed leaking tube through the use of a single analyst could be very expensive.
Quality Assurance personnel informed the inspector that Duke Power had recognized the economic risk and had begun the process of establishing a second review in July 1987.
Our plans were to have personnel trained and i
procedures in place to implement a second review of eddy current inspections no later than February 1, 19e3 fc. all steam generators.
,e were able to meet this schedule for implea ting a second review.
The incident in question was due to personnel error. The defect indication in tube R49/C64 was relatively small in amplitude and located at the roll transition area at the top of the tubesheet. Geometry changes and the proximity of the tubesheet edge produce large amplitude signals in this region, making recognition of small signals difficult. The defect signal
Violation Raponse
.Page Two
-in tubq R15/C77 was located in a free span area and was not affected by any geometry ' changes or structural items; however, the signal was small in amplitude and ambiguoue in nature. The signal was noticed but misinterpreted by the analyst.
(3) Corrective A$tions Taken and Results Achieved The flaw signals in these two tubes were discovered by the Duke analysts lement the second review program. The review who were being trained to imp"n visual indications on Tube R49/C64 found was initiated by Duke based o W
while performing a secondary side visual inspection.
Duke Power has re-evaluated all eddy current test data taken at Catawba during the August 1987 outage. No other cases of misinterprutAtion were found.
Since implementation of a second review of eddy current inspections, 23,814 individual tube inspections have received a second review. First analysis by the contractor properly dispositioned 23,810 tubes or 99.9% and properly identified 53 of 57 or 93% of the pluggable indications. These numbers include the tubes identified in this alleged violation, and do not indicate inadequate control measures. On the contrary they are indicative
-)
of proper control of a process involving human judgement.
In addition out of approximately 200,000 steam generator tube ET inspections on the Duke
+
nuclear system, no steam generator tube leaks have occurred as a result of misinterpretation of ET data.
In summary, the procedures in place at that time provided adequate measures to control ET testing of steam generator tubes to meet the Regulation requirements and Duke Power commitments. Program changes that started in July 1987, indicate that Duke Power also recognizes the economic concerns and risk of not having an independent second analysis of eddy current inspection data. This is not a programmatic violation.
(4) Corrective Actions to be Taken to Avoid Further Violations The corrective actions outlined in (3) above will avoid further violations.
(5) Date of Full Compliance Duke Power Company is presently in full compliance and maintains that adequate measures to control and accomplish nondestructive testing have always been maintained.
_