ML18113A719
| ML18113A719 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 12/20/1978 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| 703A, NUDOCS 7812260252 | |
| Download: ML18113A719 (4) | |
Text
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VIRGINIA ELECTRIC AND POWER COMPANY RXCHMOND,VXRGXN.IA 23261 Dec~mber 20;-1978 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation Attn: Mr. Albert Schwencer, Chief Operating Reactors Branch 1 Division of Reactor Licensing U. Sa Nuclear Regulatory Commission Serial No.
PO/DLB:scj Docket No~_
License No.
703A 50-280 DPR-32 Washing~on, D~ Ce 20555
Dear Mr.,
Denton:
REGULATO~Y DOCr{ET FJtE COPY SURRY POWER STATION UNIT NO. 1 STEAM GENERATOR INSPECTION This is a supplement. to our letter of December 12, 1978 which requested an amendment to Operating License DPR-32 to extend operation for an addition-al nine months from the compl~tion of the current steam generator inspection programo This letter provides clarification of the inspection progr~~ a summary of initial inspection results, and defines areas of additional inspection..
identified to dat~e The attachment to our.December 12, 1978 letter; included a description and diagram of the inspection program.
As in past inspections, the hot leg inspection boundary encompasses the 15% strain boundary as determined by finite element analysis. The cold leg inspection boundary is based-on-the 17.5% strain boundary and past experience. -The use of the 17.5% strain boundary for the cold leg is based on the minimal number of de~ting indica-tions found in previous inspections. The validity of this approach is confirmed by the cold leg inspections completed thus far during this outage..
As discussed below, the cold leg inspections in all steam generators are complete with satisfactory results.
As in previous inspections, wherever a restricted tube is found close to the inspection boundary, the inspection will be expanded in that area~
Specifically, for any tube which does not pass the.* 650" probe, all of its surrounding tubes for a distance of 2 tubes in all directions will be tested, this process continuing until no further indications are foundo Inspection Results to Date As of December 19, 1978 the initial hydrostatic test and leakage inspection and cold leg gauging had been completed on all steam generators.
Results are as follows:
7 8 1 2 2 6 0 oZ5..2J
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. L VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. Harold R. Denton 2
Steam Generator "A" To identify leaking tubes or tube plugs, the steam generator secondary side is pressurized to approximately 200 psig, and the primary side of the tube sheet is inspected for any evidence of leakage.
In steam generator "A", seven (7) plugs were wet indicating the possibil-ity of leakage.
Since the pressure differential imposed by this test is opposite to that experienced during operation, and since operating pres*sure would tend to seat the plugs, it is concluded that these plugs did not leak significantly, if at all, during operation. All seven suspect plugs will be weld repaired prior to startup.
No indication of leaking tubes was found in.steam generator "A".
- The cold leg inspection of steam generator i'A", as defined in our December 12, 1978 letter, is completea All tubes met the guaging criteria
- with a.610'° probe and all tubes were satisfactorily U-bend inspected.,
Steam Generator B There were no indications of any tube leakage or plug leakage in steam generator "B".,
The cold leg inspection of steam generator nB", as defined *in our December 12, 1978 letter, is complete. All tubes met the gauging criteria with a.610" probe and all tubes were satisfactorily*U-bend inspected..
Steam Generator. C Five (5) tubes in steam generator "C" indicated obvious or possible leakagec The suspect tubes and the apparent degree of leakage are as follows:
l} Row 5 8 Colu1Iir1 69 This tube*was the only tube which released a continuous stream of water and was therefore identified as the cause of the shutdown.
- 2)
Row 3, Column 76 This tube was merely wet, and therefore suspect, and is not believed to have contributed significantly to the leak rate prior.
to shutdowng
- 3)
Row 17, Column 8 This tube had a slow drip and is not believed to have contributed significantly to the leak rate prior to shutdowna
VIROINL-\\ ELECTRIC AND POWER COMPANY TO
- Mr. Harold R. Denton
. 3
- 4)
Row 25, Column 64 This tube had a slow drip and is not believed to have contributed significantly to the leak rate prior to shutdown.
This tube has been inspected with a.720" probe and OD wastage of approximately 80% was found immediately above the tube sheet, within the area of sludge accumulatione Accurate determination of the extent of wastage is difficult due to the presence of masking signals which have been tentatively attributed to the presence of minor denting~
This tube was inspected in May of 1978 under Regulatory Guide 1.83 and was found to have approximately 30% OD wastage.
- 5)
Row 29, Coltimn 61 This tube had a slow drip and is not believed to have contributed significantly to the leak rate prior to shutdow'"ll.
This tube has been inspected with a e 720n probe and OD wastage,-of approximately 80% was found immediately above the tube sheet, within the area of sludge accumulationu Accurate determination of the extent of wastage is difficult due to the presence of masking signals which have been tentatively attributed to the presence of minor denting.*,
This tube had not been previously inspected.
Additional Inspections
\\
Based on previous experience and on current inspection results the following tubes will be inspected in addition to those identified in our
' December 12, 1978 submittal s All Stel!m*Generators:
- JEl.ow.13, Column 79
. Row 1.4, Col~ 79
. Row 19; Columns 17 through 24
.Row 20, Columns 17 through 24 Row 21, Columns 17 through 24 Row 23,
- Column 11 Row 30, Column 77 and 78 Steam Generator*ncrv Additional inspections will be made in the areas around the following tubes:
Row 25, Column -6*4 Row 29, Column 61 The extent of. the inspection around these tubes bas not been finalized at this time..
- U
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VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. Harold R. Denton 4
We will continue to keep you informed of additional inspec~ions and inspection results.
Very truly yours,
&. )}?, 0ldt&~"r/
- c. M. Stallings Vice President-Power Supply 5nd Production Operations