ML18227D475
| ML18227D475 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 07/15/1977 |
| From: | Robert E. Uhrig Florida Power & Light Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18227D475 (6) | |
Text
U.S. NUCLEAR REGULATORY C SSION NRC FOP'95 i I2 7S)
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NRC DISTRIBUTION FDR PART 50 DOCKET MATERIAI DOCKE NUMBER FILE NUMBER TO: Mr. George Lear FROM'PL Miami, Fl.
33101 Robert E. Uhrig DATE OF DOCUMENT 07-15-77 DATE RECEIVED 07-18-77 ER RIG INAL COPY 0 NOTO8 IZE0 UNCLASSIFIED PROP INPUT FORM NUMBER OF COPIES RECEIVED S'ESCRIPTION
'O NOT REMOVE 1 page Oonsists of Status of the Examination of Turkey Point Unit 4, Steam Generator Tubes R2-C49 and R42-C53...
1 page ACKNOWLEDGEQ TURKEY POINT UNIT g 4 jcm 07-18-77 E
MANAGER; EN ING ASSISTANT FOR ACTION/INFORMATION ENVIRHNMENTAL ASSIGNED AD:
Ve MOORE LTR BRANCH CHIEF.
PROJECT MANAGER:
LICENSING ASSISTANT:
INTERNALD IST Bo HARLESS Rl BUTION TFMS SAFETY HEINEMAN EDER PLANT SYSTEMS TEDESCO BENAROYA SITE SAFETY &
ENVIRON ANALYSIS DENTON & MULIER ENGINEERING IPPOLITO OPERATING REACTORS ENVIRO TECH ERNST BALLARD GBLOOD V
Z CZY CHECK AT I LTZMAN BERG EXTERNAL DISTRIBUTION BAER B
ER GRIME GAMMILL 2
SITE ANALYSIS VOLI2IER BUNCH J0 COLLINS CO ROL NUMBER TIC REG IV J
HANCHETT 16 CYS ACRS SENT CA GO Y NRC FORM 195 (2-7B)
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NSIC 90i3y
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FLORIDA POWER 5 LIGHT COMPANY Office of Nuclear Reactor Regulation Attention:
Mr. George Lear, Chief Operating Reactors Branch 13 Division of Operating Reactors U.
S. Nuclear Regulatory Commission bashing'-on, D.C.
20555
Dear Mr. Lear:
Re:
Turkey Point Unit 4 Docket No. 50-251 Steam Generator Tube Samples Laborarorv Anal sis July 15, 1977 L-77-224 t le%
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giY Samples of two tubes were removed from steam generator "4C" during the current refueling outage and analyzed by our NSQS vendor.
Tne results of the analysis are attached for your information.
Very truly yours, obert E. Uhrig Vice President REU/MAS/ms httachmcn cc:
Mr. Norman C. Moseley, Region II Robert Lowenstein, Esquire 771990j34 HELPING BUILD FLORIDA
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STATUS OF THE EXAMINATIONOF TURKEY POINT UNIT 4 STEAM GENERATOR TUBES R2-C49 and R42-C53 Two hot leg tubes were removed from FPL Unit 4 S/G C and sent to the Westinghouse Research and Development Center for examination; Tube R2-C49 contained five support plate locations.
The non-destructive phase of the examination consisting of photo documentation, eddy current examination, radiography, and dimensional characterization is complete.
Eddy current examination indicates large amounts of tube distortion at most intersections.
Radio-graphic examination shows apparent cracking at the fourth support plate region.
All support regions show slight material density variations.
4 Destructive examination to date has concentrated on the fourth support plate intersection in the area of crack indications.
Preliminary metallographic examinations revealed OD initiated intergranular cracking to a depth of approximately 0.010 inches and ID cracking to a depth of approximately 0.003 inches.
Work is continuing to further document these findings.
Numerous metallographic samples have also been cut and mounted from other areas on this tube.
Examination has not been completed on these samples due to an urgency to obtain data at the fourth support locations.
r Tube R42-C53 was removed to some distance above the tube sheet but not including the first support.,
Eddy current findings show a 35% low volume, OD initiated indication in the area which corresponds to above but near the top of the tube sheet.
Radiographic examination shows slight wall loss associated with that area.
OD dimensional traces also show a reduction of the diameter by approximately
.010" at the top of the tube sheet.
Tube wall thickness measurements taken in what appears to be the thinned region (35% E.C. indication) show a wall loss of approximately 0.013" in a very localized area.
Metallographic examination in the area near the thinned region shows wall loss of approximately
.005". It is possible that to date we have not polished into the area of deepest attack.
This area, along with the immediately surrounding
- area, is covered with black corrosion products, suggesting that active corrosion was taking place sometime ago.
Examination of the corroded area is continuing.
The corrosion attack of this tube at a location just above the tube sheet is analogous to the incidence of phosphate thinning attack which has been confirmed in the Turkey Point and other plants.
This corrosion has occurred during the period when phosphate chemistry control was maintained in the steam generators and also for some period after the units converted to AVT control.
After con-version to AVT, residual phosphates in the sludge have been responsible for continued thinning, although diminishing in incidence.
Qi-