ML20197B634
| ML20197B634 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/28/1986 |
| From: | Wilson R GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5000-86-1064, 5211-86-2189, NUDOCS 8610300353 | |
| Download: ML20197B634 (8) | |
Text
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GPU Nuclear g
me8r 100 Interpace Parkway Parsippany. New Jersey 07054 201 263-6500 TELEX 136-482 Wnter's Direct Dial Number:
October 28, 1986 5000-86-1064 5211-86-2189 Office of Nuclear Reactor Regulation Attn:
J. F. Stolz, Director PWR Projects Directorate No. 6 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Stolz:
Three Mile Island Nuclear Station Unit 1 (TMI-l)
Operating License No. DPR-50 Docket No. 50-289 Laboratory Analysis of Pulled Tubes By letter dated February 19, 1986, GPU Nuclear Corporation informed you of our intention to remove portions of up to three tubes from the TMI-l 0TSG durino the next refueling outaae, designated 6R, as part of our ongoing evaluation' of the TMI-l OTSG's. On September 22, members of my staf f met with representatives of the NRC to discuss our program for evaluation of the OTSG's during 6R, which includes the laboratory analysis of pulled tubes as well as eddy current examination.
The 6R eddy current inspection will be in accordance with Technical Specification 4.19 as auamented by the inspection plan outlined in TR-008, Rev. 3 " Assessment of TMI-l Plant Safety for Return to Service Af ter Steam Generator Repair", which was transmitted by letter dated September 14, 1983.
We believe that the results of the eddy current examination will reconfirm our previous conclusions that primary side corrosion is not an onaning phenomenon.
The results of the laboratory analysis are expected to confirm our previous conclusions with respect to the corrosion morphology; however, we do not expect that this laboratory analyses will differentiate between previous IGA /IGSAC or any newly formed IGA /IGSAC.
The analysis will also provide further confirmation of the adequacy of the eddy current program.
We have established the objectives of the laboratory analysis as:
(1) correlation of field eddy current data with destructive analysis results; (2) further evaluation of eddy current sensitivity and accuracy by incorporation of the results into the process qualification data base; (3) detennination of the extent and type of dearadation in each tube; and (4) characterization of surface film oxide by microanalytical technique.
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GPU Nuclear is a part of the General Pubhc Utihties System
. In determining candidate tubes for analyses, GPUN identified tubes in one generator, OTSG A, which have exhibited indications above the fifteenth support plate during previous eddy current examinations.
This initial screening identified nine candidate tubes. Historical data on these tubes from 1986 and 1984 eddy current examinations, as well as 1982 results, where available, are provided in the attached Table 1.
GPUN believes that analysis of three tubes will provide sufficient information to confirm our previous evaluations, while limiting occupational exposures associated with the removal process and minimizing compromise to the Generator associated with the removal of good tubes.
In determining the best candidates for analysis, GPUN used the following evaluation criteria:
1.
IGA potential based on multiple indications in close proximity 2.
" Grain dropout", as sugaested by a decrease in throuahwall with a corresponding increase in sional amplitude.
3.
Relatively strong signals (voltage) and throuahwall extent approaching the plugging limit.
4.
Removal capability, based on dome height which dictates the maximum length of tube segment which can be removed without cutting.
This criterion has ramifications in ALARA considerations as well as sample adequacy.
5.
Indications detected by.540 Standard Differential probe but unconfirmed by 8 x 1 absolute probe.
Each of the nine candidates was evaluated in terms of these criteria, and ranked accordingly, as shown in Table 2.
While none of the tubes individually satisfies all five selection criteria, the three selected tubes (A-141-3, A-8-45, A-35-83) do, in con,iunction with one another.
These nine candidate tubes will undergo in-situ eddy current examination at the beginnino of the outaae, and the comparative rankino is subiect to change based on this inspection. Also, since the removal of kinetically expanded tubes is a relatively new process, tubes other than the three preselected tubes may be removed if difficulties are experienced durino the removal process.
GPUN also intends to perform a burst test on a portion of a tube removed from service to demonstrate the strenath of the tube.
. GPUN believes that our tube selection process and program for laboratory analysis are in accordance with the NRC conunents provided by letter dated May 2,1986.
n S cehly, F W Vice President Technical Functions RFW/SK/pa(4081f) cc:
R. Conte J. Thoma I
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TABLE 1 OTSG A TUBE PULL CANDIDATES FOR OUTAGE 6R
~
1986 1984 1982 Indication 1986
.540 1984
.540 1982
.540 8xl 8x1 8xl Dome Axial (Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
Row Tube Height Location V
V V
Coils Volts Coils Volts Coils Volts t
8 45 24.6 15+39.5 26 1.7 26 1.8 S/N
.5 1
.9 1
.6 NA f
i 15+36.8 33
.8 36
.9 NDO 2
.8 1
.9 NA 15+35.8 23 1.1 30 1.0 NDO 1
.5 1
.6 NA 15+33.5
< 20
.7 S/N
.6 NDO 1
.2 1
.4 NA 15+30.7 4 20
.7 26
.7 N00 NDO 1
.5 NA 15+30.1
< 20
.6 4 20
.8 NDD N00 1
.4 NA 18 84 15.8 15+41.9 23 1.3 23 1.8 S/N
.7 1
1.5 1 (1)
.3 NA 15+40.8 33 cl.0-33 1.1 S/N
.4 1
.4 1
.5 NA 15+39.7 S/N
.6 NDO S/N
.3 NDD 1
.5 NA 15+38.2 23 1.5 33 1.6 S/N
.5 1
1.3 1
.5 NA 15+36.7 S/N
.5 S/N
.7 S/N
.2 NDO NDO NA d
15+35.9 26
.9 20 1.2 S/N
.4 1
.2 1
.4 NA 15+34.5 23 1.2 30 1.4 S/N
.5 1
.6 1
.6 NA 15+33.9 4 20
.9 26 1.0 S/N
.3 NDD NDD NA y
/
~-
15+33.6 S/N
.5 ~
NDD NDO NDO NDO NA 15t33.1 4 20 1.3 30 1.4 S/N
.6 1
.3 1
.4 NA 15+32.6
< 20 1.1
<20 1.2 C/N
.6 1
.5 1
.5 NA 15+31.7
<20 1.1 4 20 1.4
' S/N
.6 1
.2 1
.4 NA 15+31.3
<20 1.0
< 20 1.3 S/N
.5 1
.6 1
.3 NA l
S/R Low Signal to Noise Ratio (( 3:1)
NDO No Detectable Discontinuities IDC ID Chatter 4
7 i
i i
I l
TABLE 1 OTSG A TUBE PULL CANDIDATES FOR OUTAGE 6R 1986 1984 1982 Indication 1986
.540 1984
.540 l')S2
.540 8=1 Sul 8:1 Dome Axial (Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
Row Tube Height Location V
V V
Coils Volts Coils Volts Coils Volts 141 3
16.8 15+39.9 S/N
.6 S/N
.6 N00 N00 1
.2 MA 4
15+37.6 4 20
.7
< 20
.8 S/N
.4 N00 1
.2 NA 15+36.9 26 1.0 23 1.0 S/N
.4 1
.3 1
.6 NA 15+35.8 33 1.0 36 1.1 S/N
.4 1
.5 1
.5 NA 15+34.3 30 1.6 33 1.7 N00 1
.7 1
.7 NA 15+32.6 26 1.1 26 1.3 S/N
.3 N00 1
.5 NA 15+32.1 S/N
.7 S/N
.7 N00 1
.2 1
.4 NA 15+30.4 30 1.3 33 1.4 S/N
.4 1 (1)
.4 1
.5 NA 15+27.6
< 20
.8 S/N
.8 S/N
.4 1
.4 N00 NA 15+26.7 N00 S/N
.6 N00 N00 N00 NA 15+25.3 26 1.1 26 1.1 N00 N00 N00 NA 15+22.7 S/N
.7 S/N
.8 N00 1
.3 1
.4 NA 15+15.3 S/N
.8 S/W
.7 N00 1
.3 1
.3 NA 15+15.0 S/N
.9 S/N
.9 N00 1
.4 1
.4 NA 1
15+07.8 23 1.2 23 1.3 S/N
.5 1
.4 1
.7 NA 15+07.5 d:20
.8 23
.8 S/N
.3 1
.4 1
.5 NA 15+04.5 S/N
.7 S/N
.6 S/N
.2 1
.2 N00 NA (1) 2-1 coil indications at this evaluation, not adjacent coils.
J
TABLE 1 OTSG A TUBE PULL CANDIDATES FOR OUTAGE 6R 1986 1984 1982 Indication 1986
.540 1984
.540 1982
.540 8x1 8x1 8x1 Dome Axial (Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval) i Row Tube Height Location V
V V
Coils Volts Coils Volts C0115 Volts 5
3 15.8 15+43.9 23 1.5 23 1.5 NDD 1
.4 1
.4 N/A 15+44.6 36 2.4 36 2.2 S/N
.3 1
.5 1
.3 N/A i
00 126 21.6 15+02.0 DNG
.6 DNG
.6 DNG
.6 N00 N00 N/A 15+12.5 S/N
.5 S/N
.5 S/N
.3 N00 N00 N/A 15+13.5 S/N
.6 (20
.7 S/N
.4 1
.2 1
.2 N/A 107 120 14.4 15+44.8 4 20 1.6 26 1.4 S/N
.4 1
.4 1
.2 N/A 107 2
17.2 15+33.4 sf20 1.6 30 1.5 S/N
.3 1
.5 1
.8 N/A 15+37.5
<20 1.4 20 1.4 S/N
.5 1
.4 1
.1 N/A DNG - Ding
m.__._
TABLE 1 OTSG A TUBE PULL CANDIDATES FOR OUTAGE (R 1986 1984 1982 Indication 1986
.540 1984
.540 1982
.540 8xl Rxl 8xl Dome Axial (Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
(Re-eval)
Pow Tube Height Location V
V V
Coils Volts Coils Volts Coils Volts 35 83 42.9 15+35.6 46 1.4 46 1.1 N00 1
.6 1
.5 NA i
103 121 20.6 15+44.3 33 1.0 43 1.1 N00 1
.8 1
1.0 NA 15+43.9 36 2.1 43 2.1 S/N
.7 1
1.1 1
1.2 NA i
I 4
t i
I
TABLE 2 COMPARATIVE RANKING
- OTSG A TUBE PULL CANDIDATES FOR OUTAGE 6R TUBE NO.
IGA / MULTIPLE GRAIN STRONG EASE OF SCREENED INDICATIONS DROPOUT SIGNAL REMOVAL INDICATION /
UNCONFIRMED A-141-3 Yes Yes Moderate No Yes A-8-45 Yes Possible Moderate Moderate Possible A-18-84 Yes Possible No No Yes A-35-83 No No Yes Yes No A-103-121 Moderate Possible No No No A-107-2 Moderate Yes No No No A-60-126 Yes No No Moderate No A-107-120 No Yes No No No A-5-3 Moderate No No No No
- In ranking the candidates, a "Yes" was assigned 2 points, a "No" was assigned 0 points, and other responses were assigned 1 point.
_ - _ _._