ML20077D400
| ML20077D400 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/20/1983 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-83-208, NUDOCS 8307260509 | |
| Download: ML20077D400 (2) | |
Text
.s GPU Nuclear Corporation
- ' NggIgf Post Office Box 480 Route 441 South Middletown, Pennsylvania 17057 0191 717 944 7821 TELEX 84 2386 Writer's Direct Dial Number:
July 20, 1983 5211-83-208 Office of Nuclear Reactor Regulation Attn:
J. F. Stolz, Chief Operating Reactor Branch No. 4 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50--289 TMI-l Steam Generator Repair Status Update Our letter of June 13, 1983 (5211-83-179), informed you of results of post repair testing of the steam generators performed to that date and plans for future testing. This letter is to inform you of additional test results through early July including the early results of reactor primary system cleaning.
Following repair of the residual tubes identified in our June 13, letter, we conducted additional drip and bubble tests of both OTSG's on June 17 and June 26.
These tests on OTSG "B" showed no observable leaks. The drip test on OTSG "A" identified five plugs (four rolled plugs and one explosive plug bottom tube sheet) and one tube with drops of water clinging to the end.
No drops were seen to fall free over the 30 second observation period from any of these six tubes. This particular tube (unplugged) had been inspected by ECT in the previous month and dispositioned as no detectable defects. This tube was not plugged. The leakage from the plugs was extremely small and since future operation may seal the plug leakage with time, no further repair action regarding the dripping plugs is planned at this time.
The bubble test on OTSG "A" identified seven plugs (one welded and six rolled) and three unplugged tubes from which some gas bubbles were detected by visual observation. The welded plug was repaired. This was the first bubble test on this welded plug since it had been repaired.
All of the tubes and rolled plugs passing nitrogen in OTSG "A" had very fine streams of tiny bubbles which did not cause surface disturbances of the water layer.
This amount of bubbling is less than that observed in previous testing.
D,ue to the small amount of leakage, no further action was taken regarding the three tubes and six rolled plugs. The results of pre-critical hot functional OTSG testing will be used to disposition these tubes prior to critical plant operation.
GPU Nuclear Corocration la a subsidiary of the General Public Utilities Corporation 8307260509 830720 PDR ADOCK 05000289
/l 9
.o Mr. J. F. Stolz 5211-83-208 L As indicated in' the June 13 letter, we are continuing to eva.1.uate all testing of. the steam generators and will assess that information at the management review following steam generator hot. testing.
The Staff will be informed of GPUN's conclusions prior to proceeding to criticality.
We have completed approximately 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> of RCS cleanup.
The sulfur level
.(measured as. sulfate) in the RCS water shows a slight increase as a function of time. 'The sulfate has increased from an initial value of 220 ppb to approximately 360 ppb as of July 18.
This sulfur increase is substantially less.than predicted based on assuming the maximum levels of contamination drawn from swipe data from the areas of highest concentration (i.e., OTSG upper head area).
- Throughout the RCS cleanup, we have been. monitoring for primary to secondary leakage by examining the secondary side for activity. No tritium has.been detected to date. Tritium is currently 4.4 x 10-3 uci/ml in the RCS and has a minimum detectable activity of about 5 x 10-6 uci/ml.
It'one assumed equal mixing in the OTSG secondary side, the Icah, if any, at the current 300 psi differential pressure is less than 2 x 10-3 gpm based on no detectable-
~ tritium. There have been several Cesium-137 measurements above the minimum detectable activity of 1 x 10-7 uci/ml.
These measurements have been l
interspersed with measurements below the minimum detectable activity.
The highest secondary side Cesium-137 activity which was measured after 10 days is 1.86 x 10-7 uci/ud.. Since Cesium-137 is currently 1.6 x 10- uci/ml in the RCS, this corresgonds to a' primary to secondary leak rate of equal to or less than 2 x 10-gpm.
L0ur schedule shows completion of the 400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> scheduled-RCS cleanup on July
~
24 with 6'to 10 days required to restore RCS chemistry to its normal opera-tional range. Tha expect to be prepared to commence pre-critical hot testing
- of the steam generators starting very early in August.
Sincerely, Q
/2, D.Lihkill Director, TMI-l
. HDH: DGS:vj f cc:
-H.
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