ML20115D160
| ML20115D160 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/14/1992 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9210200267 | |
| Download: ML20115D160 (3) | |
Text
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I Northem States Power Company 414 Nicollet Mall IAnneapolis, Minnesota 55401 1927 T;ts phone (612) 330-5500 October 14, 1992 Technical Specification 4.12.E.1 I
U S Nuclear Regulatory r'ommission Attn:
Document Control Desk Washington, DC 20555 i
PRAIRIE IS1AND NUCLEAR GENERATING PIANT Docket Nos. 50 282 License Nos DPR-42 50 306 DPR-60 11.eam Generator Tube Pluggine and Sleeving In accordance with Technical Specification 4.12.E.1, the following steam generator tube plugging and sleeving information is provided for the information of the NRC staff.
Following the recent inservice inspection of Unit I steam generator 12, twenty-seven tubes were plugged for the first time.
Because steam genera'or 11 was not examined during this outage, the percentage of tubes plugged in steam generator 11 remains 2.15%.
The percentage of tubes plugged in steam generator 12 is 3,14%,
A summary is attached.
Per Technical Specification 4.12.E.1, this information will be expanded upon in an Inservice Inspection Report for Unit I which will be submitted to the NRC within 90 days of the completion of this inspection (October 2, 1992),
Also, Table 4.3 13 of the Prairie Island Updated Safety Analysis Report will be updated in the next revision.
If you have any questions concerning this information please call.
g
/ }ggp n omas M Parker Manager Nuclear Support Services c: Regional Administrator - Region III NRC Senior Residens Inspector, NRC NRR Project Manager, NRC Jay S11 berg
Attachment:
Steam Generator Tube Plugging / Sleeving Summary j
9210200267 921014
' (i i
PDR ADOCK 05000282 O
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Attachment UthRC y
m:tdwr 14, iM2 Page 1 of 2 STEAM GENERATOR TUBE PLUGGIMG/SLEEVINC
SUMMARY
Steam Generator.Fo. 11 9pmmary New Indications Plugged This Outage:
0 Total Tubes Plugged:
73 Total Tubes Sleeved:-
0 11 Steam Generator % Plugged:
2.15%
Plug Removal: No plugs were removed in response to NRC Bulletin 89 01 j
during this outage, i
l New Indications Steam Generator 11 was not examined during this out.ge to repair a tube leak in Steam Generator 12.
Tube Plug Insoceti2Hi j
No plug examination was done in Steam Generator 11.
Stenm Generntor No 12 Summar7 i
4 New Indications Plugged This Outage:
27 4
New Indications Sleeved This Outage:
O Sleeved Tubes Plugged This Outage:
0 Total Tubes Plugged:
99 i
Total Tubes Sleeved:
167 I
12 S/G % Plugged + % Sleeved Equivalent:
3.14%
L Plug Removal: No plugs were removed in response to NRC Bulletin 89-01 during this outage.
i
}
New Indications:
Twenty seven defective tubes, all with indications in the tubenhuet j
crevice region were identified:
l l
Sixteen af these tubes had multiple axial indications in the tubesheet crevice region.
Eleven of these tubes had single axia' indicatJons in the tubesheet crevice region.
i These indications are typical of the secondary side IGA / SCC corrosion occurring in the tubesheet of 12 steam generator.
l Two of the tubes had axial indications at the top of the roll transition zone. These could have been caused by primary water stress corrosion cracking, but the data is not definitive, i-I a-i
1
)
Attachment e
USWRC l.
October 14, 1992 Page 2 of 2
+
i Defective Sleeve:
The sleeves were not examined during this outage.
Tube Pluc Inspection:
)
The tube pluS inspection in 12 steam generator was satisfactory.
Tube Leakare Identification:
1 The primary to secondary leak rate in 12 steam generator was 0.1~gpm prior to the Unit 1 shutdown.
Three tubes were identified with through wall leakage..The major source of this leakage was tube R13C43 which.
had a long axial indication in the lower 11 inches of the tube just l
above the roll transition region.
Leakage of two drops per minute was observed with the steam generator full of water.
Two additional tubes, R15C40 and R2C49 were found to be leaking after-j steam generator 12 had been pressurized to 700.psig for two days.
Both of these tubes had short multiple axial indications just above the roll 4
transition.
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