ML17341A053
| ML17341A053 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 12/10/1980 |
| From: | Underwood P GEORGIA POWER CO. |
| To: | |
| Shared Package | |
| ML17341A054 | List: |
| References | |
| NUDOCS 8012230301 | |
| Download: ML17341A053 (15) | |
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FLORIDA PO'e'C~FS 6 I IGHT CO)APAIIY December 18, 1980 L-80-412 Office of Nuclear Reactor Regulation Attention:
Hr. Darrell G. Eisenhut.
Director Division of Licensing U.
S.
Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Eisenhut:
Re:
Turkey Point Unit 4 Docket No. 50-251 Steam Generator Ins ections The results of the Turkey Point Unit 4 steam generator inspections conducted during the current outage are attached.
The inspections which were performed in accordance with Turkey Point Unit 4 operating license DPR-41 showed Jio new phenomena and verified that the general pattern of denting in Unit 4 is within predictable limits and-consistent with previous inspections of the Turkey a
Point Units.-
The general criteria applied for steam generator inspections and preventive...,
. plugging are the same as previously applied to Turkey Po~nt Units 3 and 4.
This approach provides reasonable assurance of steam generator tube integrity such that safe operation of the unit during normal full power operation and during hypothetical accident conditions is assured for an operating period in excess of six equivalent full power months.-
Therefore, the implementation of this program with the resulting preventive plugging, enables continued safe.
full power operation of Turkey Point Unit 4.
Total steam generator tube pluggi~nat the conclusion of the current outage mil1 ba approximately 2X8%
Th'is.>s c
bounded by the 255 tube piogging ECCS analysis.
The results of this inspection and the preventive tube plugging program have been reviewed by the Turkey Point Plant Nuclear Safety Committee and the Florida Power 5 Light Company Nuclear Review Board.
They have concluded that based on the inspection results, the implemented plugging pattern.
and previously submitted analyses, that the return of Turke Point Unit 4 ull power ~o eration for at least six e uivalent. months does not involve an unreviewed safety ques ion.
In accordance with condition D.1 of operating license DPR-41, Florida Power. 5 Light Company requests permission to return Unit 4 to power operation for a period of six equivalent full power months.
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'EOPLE...SERVING PEOPI.E
Darrell G. Eisenhut Office of Huclear Reactor Regulat'.'n Page 2
Based on our current schedule, we could be ready to resume power operation by January ll, 1981.'e will keep you advised of any significant changes.
We have determined that this is a Class III request in accordance with 10 CFR 170.
Accordingly, a check for $4,000 is enclosed-Very truly yours, Vice President Advanced Systems 8 Technology REU/RJA/ras Attachment cc:
J. P..O'Reil ly, Region II Harold F. Reis, Esquire
~
'ue to the local plate crack--g that
'.s believed to occur. at the Deripnery ano near wedge locations, tube leaks may occur here at lower levels of tube re-striction than in the tubelane.
Thus, the wedge areas should have their own inspection program and plugging criteria.
The plugging criteria at.hot leg wedge locations calls for treating leakers and tubes that restrict the 0.540 inch probe in a similar manner.
En addition, tubes that restrict the 0.610 inch probe hand peripheral tubes that restrict the 0.650 -inch probe. should be plugged.
Cold leg plugging will be based on the degree of activity noted and rates of progression observed from gauging.
'I The plugging criteria which support at least ten months of operation are:
l.
All tubes which do not pass.the 0.540 inch probe will be plugged.
2.
Additionally, for in excess of ten (10) months operation, two (2) tubes beyond (i.e.,- higher row numbers) any tube in columns 1-92, in'the tube and region which did.not,pass the u.540 incn probe will be plugged.
Calculation of the progression of the 17 1/2X strain contour, as determined from finite element plots through 24 EFPN after closure results in predicted advancement of this contour by ]
9 tube now for a 10 month operating period.
Given the conservatism of this approach, p ugging wo i g two additional tubes beyond observed 540 mils restrictions provi'des'dequate margin. This criterion was applicable for only one 540 mil restriction, i.e.
S/G'C, R3-C64, in this inspection.
J 3.
All tubes. which do not pass the 0.610 inch probe will be pluggea.
5.
The tubes in any column for which plugging under criteria (1), (2),
or (3) above is implemented
-in the tubeiane region will also be plugge in the lower row numbered tubes back to the tubelane if not already plugged.
As a conservative
- measure, tubes completely surrounding any known leaking tubes including the diagonally next tube will=be plugged -if.-not. already covered by the -foregoing criteria.
6.
In any given-column which is surrounded by columns containing tubes with significant tube restrictions or prior plugging, (thereby creating a
"plugging valley" in the pattern) engineering judgement will be used to fill the bottom of the valley.
In the peripheral tubelane areas near the three and nine-o.-'clock wedges, tubes surrounded by previously plugged tubes or tubes exhibiting-.high-deformation activity will..be plugged, based on engineering.,judgement.-:
Parti ttention was paid to 650" restricted tubes relative to the ten month operating period.
7.
Additio>>ai p>inventive plugging will be'implemented at.the hot. leg wedge locations.
This plugging will include all tubes that:
a.
Restrict the 0.540 inch probe..
b.
Restrict the 0.610 inch probe.
c.
Restrict the 0.650 inch probe at the periphery.
d.
Surround leakers and tubes that restrict the 0.540 inch probe.
including the diagonally next tube.
8; Application of the criteria specified in 7 above, will be made on the basis of engineering judgement for cold leg wedge locations.
9.
Additional preventive plugging will be implemented in the patch plate region.
This plugging will include all tubes that:
a.
Restrict the 0.540 inch probe.
b.
Restrict the 0.610 inch probe.
c..
Surround leakers and tubes that restrict the 0.540 inch probe including the diagonally next tube.
d.
Lie on either sides of the patchplate boundary {plate perimeter on one side, the plug welds on the other three) and restrict the 0.650 inch probe.
The ten month operating period was also evaluated relative to a postulated main steam line break accident
{HSLB).
In doing this, it was conservatively assumed that each unplugged tube iq the two rows beyond tnt present tube-lane plugging boundary in the most advanced SG{B) would le~~. at ;.ate of 0.05 gpm/tube during a pos ulated na."" steam line break.
~Jsing i::.- :-:c hat there are 92 tubes in a ro'~'. ".hc to
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nomber o~
u:-.,
the tube'any roc'on lying adj=-"~;~= 'o
-.~e - -rert v".'."."'-." boi..".ai
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end of the 10 month operating interval is less than 184 tuoe The total leakage re"ul ing from 184 tubes is 9.2 GPM.
This aaaed to the 0.
leakage assumed to be present at the start of a postulated main steam line bre.
(which would increase to approximately 0.7 GPM due to NSLB differentia1 pressur<
yield a total leakage less than 10 GPH which has been determined in previous submittals to be an acceptable level of leakage during a postulated MSLB.
B.
Re viator Guide 1.83 The criteria for plugging tubes in this area are established in the regulatory guide.
C.
Preventive Plu in Accom lished The preventive plugging programs that were implemented to justify at least 10 morths operation are indicated in Figures 15, 16 and 17.
Both gauging 4
and Regulatory Guide 1.83 program plugging are shown on the figures.
The coordinates of the plugged tubes are listed for each steam generator in Tables 5,
6 and 7 respectively.
The cumulative percentage of tubes plugged to date is 23.8%.
Table 4 summarizes plugging performed during this outage.
TABLE 4 S/G A
S/G B
S/G C
Gauqain 37 44
SUMMARY
OF TUBES PLUGGED R.G. 1.83 18 0
E
N S
Ar
TUR"EY POINT UNIT I/4
><hv~V.'.",~~
>V.",O Ii'SP~Ci ION ENERAiilR A A.
Recomnended Plu in for Gau in Results For 6 Mo. Plu in Pro ram:
R-C 14 -
4 16-4 17-4 8-5 16-5 9-6 16-6.
17
<<6'5-9
'15 - 10 17 - ll 28 - ll 7 - 26 3 - 43 44 - 47 7 - 69 10 - 89 otal Plugging for Gauging, 6 Mos.
rogram:
17 tubes Re
. Guide 1.83 Plu in:
R-C 6-75 11 - 22 0
9-21 Total Reg.
Guide 1.83 Plugging:
3 tubes Additional for 10 Ho; Plu in Pro ram:
R-C 14 - 9 16 -11 17 - 12 18 - 12 10-88 9 - 89 9-90 Total Additional Pluqging for Gauging, 10 Mos. Program:
7 tubes 14
TURKEY t'u 4 liT NOVEMBER 19""0
.')x~PEl;TTON STEAN GEHE~TGR 8
A.Recommended Plu in for Gau in Results For 6 Ho. Plu in Pro ram:
Additio'nal for 10 Mo. Ply in Pro ram:
R-C 4
9-2 ll - 4 15 - 8 23-8 15 - 10 5-17 8 24 42 30 9-38 45 44 37 - 53 29 - 54 31 - 54 R-C 41 -65 26 - 72 37
~ 73 5 - 78 7 - 84 7-85 8-85 10 - 85 9-86 -, 89 7-89 10 - 89 11 - 89 17-89 R-C
.7 - 90 7 - 92 R-C 16 - 9 14 - 10 16 - 10 lj - 10 7 - 25 25 - 73 9 - 85 Total FPlugging for Gauging 6 Ho.
FProgram:
30 tubes.
Total Additional Pl ug ging for Gaug ing, 10 Mo. Program:
7 tubes.
8, Re..
Guide 1.83 Plu in:
IB-C R-C R-C 144-29 23-46 17-69 122 - 30 10-46 9-81 2 3 - 39 ll - 46 10 244 - 39 13 - 46 244 - 40 7 - 62 111 '- 44 7 - 64 222 - 44 7 - 65 222 - 46 Tootal Reg.
Guide 1.83 Plugging:
18 tubes.
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TURKEY POJ "T U""T "i" t'OVEMBER 1","," JVSPECT.'Q.'!
STE/N GEhERATOR C
~dd i i~id di R R'or 6 Mo~P'lu in9 ~rocrram:
Addii i
i~Ad.di idd~
R-C 22-7 14-9 42 -
31 42 - 32 42-33 42 - 36 43-36 41 - 37.
42-37 43-37 41 - '38 42R - 38 43-38 38 - 39 5-41 6 - 41 R-C 43 - 46 33-51 7-54 8-54 3-59 4-59 42-62 3-64 4-64 5-64 41 - 66
'5 - 72 8-83 8-86 9-86 9-87 9-90 R-C 15 - 8 42-34 42 - 35 43 - 45 42 46 43 - 48 41 - 63 3-65 8 - 84 9 - 85 10 - 89 Total Plugging for Gauging, 6 Mo. Program
= 33 tubes.
Total Additional Plugging for Gauging, 10 Mo. Program
= ll tubes B.
Re
. Guide 1.83 Plugging:
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5 Teta Reg Guid'a 1 8~ ?luoQ" nc:
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