ML20207H846
| ML20207H846 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 07/22/1986 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.083, RTR-REGGD-1.083 NUDOCS 8607250119 | |
| Download: ML20207H846 (4) | |
Text
e.,.
South Carolina Electric & Gas Company Dan A. Nauman P.O. Box 764 Vce President Columbia. SC 29218 Nuclear Operations (803) 748 4513 SCE&G
~
July 22,1986 Mr. Harold R. Denton Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555
SUBJECT:
V. C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPP-12 Steam GeneratorTube Repair
Dear Mr. Denton:
South Carolina Electric and Gas (SCE&G) submitted a request to revise the Virgil C. Summer Nuclear Station Technical Specification (T. S.) relative to steam generator tube repair per letter from D. A. Nauman to H. R. Denton dated January 16,1986. The proposed T. S. revision will permit the repair of steam generator tubes as an alternative to tube plugging.
As a result of a meeting between SCE&G, Westinghouse and your staffon 06-27-86, SCE&G wishes to further clarify the inservice inspection criteria of tubes which have been returned to service through repair. SCE&G will incorporate increased sampling of repaired tubes in the first two inservice inspections after the initiation of a repair technique. A representative sample of repaired tubes shall be examined as part of the T.S. required random sample at each subsequent inservice inspection. This inspection program will be documented and procedurally established. SCE&G has revised the FSAR Response to Regulatory Guide 1.83 to incorporate this commitment as indicated on the attachment.
Ifyou should have any further questions, please advise.
Very Truly Yours, D. A.Nauman DBM: DAN:ast ATTACHMENT c:
V. C. Summer R. M. Campbell O. W. Dixon,Jr./P. C. Nichols,Jr.
K. E. Nodland E. H. Crews, J r.
R. A.Stough E. C. Roberts G. O. Percival J. G. Connelly,Jr.
R. L. Prevatte W. A. Williams,Jr.
J. B. Knotts, Jr.
J. Nelson Grace H. G. Shealy Group Managers NPCF O. S. Bradham File D. R. Moore C. A: Price C. L. Ligon (NSRC) wwww y
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Scaggg((Pesh,en-a s.
Tubes for the inspection of operating plants are selected on a random basis except where previous experience in that j
plant (or in similar plants with similar secondary water j
chemistry) indicate that detectabic penetration, or defects, occur in specific areas of the tubesheet array or specific locations along the tube length.
I b.
Tube inspection means the testing of a particular section of steam generator tubing. For U-bend designs, the tube (sample) in each steam generator to be inspected is tested from either the inlet or outlet side completely around the U-bend to the top support on the opposite side.
Each steam generator in a given plant is inspected at the c.
first inservice inspection. Subsequent inspections are limited to one steam generator on a rotating basis if the i
results of the first inspection indicate that all steam generators are performing in a like manner.
(Note: Under some circumstances, the operating conditions may be found to be more severe in one steam generator than those in the other steam generators. Under such circumstances, the sample sequence is modified to inspect the steam generator with the most severe conditions).
5.
Supplementary Sampling Requirements If the eddy current inspection pursuant to Regulatory i
a.
Position C.4.c indicates that more than 10 percent of the inspected tubes have detectable wall penetrations (>20 percent) or that one or more of the inspected tubes have an indication in excess of the plugging limit (see Regulatory Position C.7.a), an additional 3 percent of the tubes are inspected, concentrating on tubes in those areas of the tubesheet array where the tubes with imperfections were L
j l
found. The additional tube inspection is only performed I
through the length of tubing required to adequately inspect the area of the sample in which defects were found.
Footnote 5 to C.S.a In all inspections, previously degraded tubes that exhibit significant (>10 percent) further wall penetration is included in the 10 percent.
Previously degraded tubes that exhibit less than 10 percent further wall penetration are not included in the 10 percent.
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b.
If this additional inspection indicates that more than 10 percent of these additionally inspected tubes have detectable wall penetrations (>20 percent) or more than three of these additionally inspected tubes have an indication in excess of the plugging limit, additional tubes (no less than 6 percent of the total tubes in the steam 3A-47 I
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generator) in the area of the tubesheet array where tubes f
with imperfections were found are inspected.
The additional tube inspection is performed only through the length of tubing required to adequately inspect the area of this additional sample in which defects were found.
7.
Acceptance Limits As used in this regulatory guide:
a.
(4)
Plugging criteria means those calculational, analytical, and/or experimental procedures used to arrive at the plugging limit.
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b.
If, in the inspections performed under Regulatory Positions C.S.a or C.S.b, less than 10 percent of the total tubes inspected have detectable wall penetration (>20 percent) and no more than three tubes exceed the plugging limit, plant j
operation may resume after required corrective measures have i
been taken.
If, in the inspections. performed under Regulatory Position c.
C.S.b, more than 10 percent of the total tubes inspected have detectable wall penetretion (>20 percent) or more than three of the tubes inspected exceed the plugging limit, the situation will be immediately reported to the NRC in accordance with the facility license for resolution and approval of the proposed remedial action. Additional sampling and more frequent inspections may be required.
8.
Corrective Measures Leaking tubes, defective tubes, and tubes with imperfections exceeding the plugging limit shall be plugged or repaired.
Repair of tube will be considered as a corrective action provided the repair is conducted in accordance with the applicable section of the ASME Code and an evaluation in accordance with 10CFR50.59 is performed.
(See Insert A) 1.84 CODE CASE ACCEPTABILITY ASME SECTION III DESIGN AND FABRICATION (Revision 18; 8/81)
Regulatory Guides 1.84 and 1.85 (first effective date:
July 1, 1974) were issued long after the issuance of the Construction Permit for the Virgil C.
Summer Nuclear Station. Only ASME approved code cases are used for code Class 1, 2, and 3 components. For Class 1 components, a discussion of code cases is contained in Section 5.2.1.4.
AEC (NRC) approval of code cases for Class 2 and 3 components was not required and not obtained. After the regulatory guides' first effective date, code cases were reviewed against those specified in these regulatory guides.
b-Insert A J
An increased sampling of repaired tubes shall be performed during the first two inservice inspections after the initiation of a repair technique. A representative sample of repaired tubes shall be examined as part of the technical specification required random sample at each subsequent inservice inspection.
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