ML19273C123
| ML19273C123 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 08/15/1979 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19273C117 | List: |
| References | |
| LER-79-012-01T, LER-79-12-1T, NUDOCS 7908270434 | |
| Download: ML19273C123 (7) | |
Text
{{#Wiki_filter:. . . . . . . . . . . . - .,... ~ ,. . . . . (7 77) LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l l lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATIONI o i 7 8 IW 9 l LICENSEE i l P lCODE B l H l 1 l@IS0 l 0 lLICENSE 14 -l 0 NUM8ER l 0 l 0 l 0 l 0 lJS- l 0 26 l 0LICENSE l@l 4TYPE 1l l l@ l 1Jo l 1$7l CATse 1 l@l CON'T ITITI " SO R% l Ll@l Of s DOCKET I 010NUMBER l 012 l s I s68 l@l69 o I aEVENT I o DATg I s I 7 l 974 @l75o I aREPORT i 1 IDATE s I 7 I o80 l@ i 8 60 Gl EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h O 2 fon 8/5/79 after coming on-line at 0118 hours following a scheduled l g l outage, an indication of a primary-to-secondary leak was noted in the l g l Unit 1 "A" steam generator. Load was maintained at 150 MWe to make leak l f3 Tin trate calculations. At 0255 hours the leak rate was determined to be 50isll1.45 gpm. The unit was taken off-line at 0300 hours, 8/5/79. This l g l event is reportable per TS 15.6.9.2.A.3 and similar to LER's 78-001/OlT l f6Tii 1 -0, 78-010/0lT-1, and 79-003/01T-0. l 7 8 9 80 E CO E S 8C E COMPONENT CODE SUSCOO'E SU E g 7 8 l C lB l@ y@ W@ l HlT l E lX l Cl H[@ {@ W @ 9 10 13 12 13 18 19 20
. SEQUENTIAL OCCURRENCE REPORT REVISION L EVENT YE AR REPORT NO. COOE TYPE NO.
O a'ER/RO uuu gP l217 22l 9l [-j 23 l0l1l21 24 26 y 27 l 01 11 N 29 lTI 30 l--J Lo_J 31 32 TAKEN A O PL NT M T HOURS 22 38 17 POR US. SU LI R MANUP CTURER [B_j@[_Z_j@ 33 J4 lAl@ 3'h [Aj@ 36 J/ Ol 2l 9l 7l lYl@ 48 lYl@ W@ Wl1l2l0l@ 40 42 43 44 47 CAUSE DESCRIPTION ANO CORRECTIVE ACTIONS g l Leak tests revealed two leaking tubes in the "A" steam generator and l
, i lseveral damo areas in the "B" steam generator. Eddy current testing l
, , grevealed 52' defective tubes in the "A" steam generator and 45 in the i g l"B" steam generator. All leaking and defective tubes were plugged. l ITITI l 1 7 8 9 80 STA 3 % POWER OTHE R STATUS Ols RY D8SCOVERY DEW *tiPTION W (F_J@ l0l3l3l@l N/A l [A_J@lOperatorobservation l ACTIVITY CO TENT RELEASED 07 RELEASE AMOUNT OF ACTIVITY LOCATION 07 RELEASE i 6
@ l Insignificant l l Priming air eiector discharae l PERSONNEL EXPOS ES NuuSER TYPE cESCRiPTiON @
l TIT] l 0 l 0 l 0 l@y@l N/A i l PERSONNE L INJURIES Nt 8M8 ER DESCRIPTION i R l 0 l 0 l 0 l@l12 N/A l 7 8 9 11 80 T E OESCR PT ON 7 i 9 8 9 y@l 10 N/A ' l S0 2 O ISSUEf@ l Y_ l Press DESCRIPTION release f l llllllllllll1; 7 8 9 10 68 69 80 3 C. W. Fay 414-277-2811 o NAME OF PREPARER PHONE: ",
ATTACHMENT TO LICENSEE EVENT REPORT NO. 79-012/OlT-0 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 1 Docket No. 50-266 When returning Unit 1 at Point Beach to service at 0118 hours on August 5, 1979, following a scheduled outage to add reinforcing to the auxiliary feed line to main feed line branch connections, indications of primary-to-secondary leakage were noted. i After phasing, the load was maintained at 150 MWe for approximately one-half hour in order to conduct leak rate measurements. At 0255 hours the leak rate was determined to be 1.45 gpm in the "A" steam generator. The unit was taken off line at 0300 hours, August 5, 1979, for repair and eddy current testing. Cold shutdown was achieved at mid-day, August 5, 1979. During leak testing under static head conditions at 1900 hours, August 6, 1979, a leaking tube was visually identified at R17C46 in the "A" steam generator inlet. A second tube, R17C44, was also found to be dripping slightly. Eddy current testing was begun late in the afternoon of August 7, 1979. Evaluation of the first 150 tubes of the initial 242 tube sample (i.e., 6% of all tubes in that steam generator plus inspection of all unplugged tubes known to have previous defects in excess of 20%) disclosed significant defects in five tubes in addition to the two leaking tubes. All the tube defects were found to be within the tube sheet crevice area. With the number of defective tubes found in the initial sample shown to be in excess of 1% of the sample, eddy current inspection of all unplugged tubes in the inlet of the "A" steam generator to the first support plate was made plus all tules in both steam generators with previous greater than 20% defects in accordance with the Technical Specifications. In addition, a sample of tubes was added in the "A" steam generator outlet as a prudent measure. Extensive examination of the "B" steam generator using a TV camera to view the primary side of the tubesheet revealed several damp tubes on the inlet side of the tubesheet. Initial leak test at 100 psig secondary side pressure did not reveal leakage; however, several hours at natural head pressure produced areas of obvious dampness on the otherwise dry tubesheet. The initial eddy current sample included these areas. Seven defective tubes in the damp areas and two additional tubes were found defective early in the initial sample testing program of "B" steam generator. Consequently it was decided to proceed
~
immediately with 100% inspection of the ."B" inlet to the first support rather than the minimum 2S, 6% sample, per the Technical Specifications. Eighty tubes were eddy current tested in the "A" outlet ' with no defects found. Because of the good results in the "A" outlet, and as no previous greater than 20% defects exist in the outlet of "B" steam generator, no testing was necessary in the "B" outlet. All eddy current testing of both "A" and "B" steam generators was completed at 0830 hours, August 14, 1979. Final results of the program disclosed 52 defects in the "A" steam generator inlet and 45 defects in the "B" inlet. All defects were below the tubesheet in the crevice area. Complete lists and maps of the defects are attached. Multi-frequency eddy current testing was performed to verify the nature of all defects initially discovered by single frequency techniques. Eight tubes initially thought to be defective in the "B" inlet using a single frequency were later shown to be acceptable for continued service by multi-frequency testing. All other defects were confirmed. ~ All defective tubes are being plugged. The following tubes were mechanically plugged on the inlet side of the "A" steam generator: R17C44, R17C46, R22C35, and R15C50. This was done to enable the two verified leaking tubes (R17C46 and R17C44) to be removed for examination at a future refueling. The outlet ends of the four tubes and each end of all of the other defective tubes are being explosively plugged. At the conclusion of plugging, an 800 psig leak test will be performed and photographs of the tubesneets will be taken to verify the integrity and proper location of the plugs. Other results of the eddy current test program indicate that any tubes which, in previous examinations had indicated defects greater than 20% but below the plugable limit of 40%, had not increased in magnitude, nor were there any new d2fects discovered in the 20 to 40% range. Tube conditions above the tubesheet were determined to be stable. It is estimated that Unit 1 will return to service the weekend of August 18-19, 1979.
EDDY CURRENT EXAMINATION RESULTS "A" STEAM GENERATOR INLET
% Depth Below Top % Depth Below Top Row Column Defect of Tubesheet (In.) Row Column Defect of Tubesheet(In.)
17 44 100 -1 25 42 79 -14 17 46 100 -1 11 44 76 -1 17 42 95 -1 27 45 81 -1 20 26 95 -1 27 46 78 -4 24 38 87 -12. 27 48 89 -10 23 35 84 -2 6 48 87 -6 to -8 22 35 76 -10 11 49 84 -8 15 48 85 -2 27 50 88 -6 to -8 17 48 91 -4 15 50 92 -1 27 54 90 -16 6 51 94 -4 24 39 87 -14 27 51 87 -2 24 34 89 -14 13 52 85 -2 10 18 69 -4 8 52 91 -1 11 20 90 -16 6 52 93 -2 to -10 9 25 96 -4 27 53 87 -14 26 25 85 -10 5 54 93 -6 to -10 9 26 89 -4 to -12 5 57 89 -8 9 27 92 -8 5 55 89 -4 to -8 20 27 67 -2 13 60 85 -2 23 30 90 -12 to -16 12 60 79 -2 21 32 90 -18 3 67 83 -12 27 36 83 -14 5 49 90 -4 25 36 82 -14 to -16 6 50 86 -4 6 36 73-86 -12 9 52 90 -1 26 37 82 -14 9 53 92 -1 27 41 83 -18 25 38 85 -12
* ~~
EDDY CURRENT EXAMINATION RESULTS "B" STEAM GENERATOR INLET
% Depth Below Top % Depth Below Top Row Column Defect of Tubesheet (In.) Row Column Defect of Tubesheet(In.)
31 40 84 -16 22 47 91 -12 to -16 22 43 94 -16 25 47 86 -14 23 46 77 -8 21 42 74 -8 to -10 , 23 48 82 -12 to -14 29 49 82 -14 6 57 94 -14 to -16 14 50 78-88 -1 to -10 11 14 83 ~16 14 51 88 -1 22 40 73 -8 22 51 74 -8 7 . 79 92 -18 22 62 88 -12 22 49 80 -12 to -14 28 65 91 -18 24 34 93 -18 18 67 81 -16 21 38 79 -4 22 52 91 -10 23 42 68 -12 26 44 90 -6 11 27 87 -1 11 28 91 -1 22 32 87 -12 5 33 85 -6 to -8 23 34 92 -6 to -10 23 36 82 -14 to -16 8 36 75 -10 21 37 86 -2 to -14 23 37 79-88 -10 to -14 23 33 93 -10 , 26 39 92 -6 25 40 68 -18 21 40 80-87 -4 to -12 8 40 96 -10 6 40 81 -10 4 40 95 -12 4 41 86 -12 21 41 66 -6 22 41 85 -16 to -18 14 42 88 -1 13 42 87 -1
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