ML20030D399
| ML20030D399 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/24/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-1005, NUDOCS 8109010352 | |
| Download: ML20030D399 (4) | |
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TENNESSEE VALLEY AUTHORITY:}iC 7 M CH ATTANOOG A, YENNESSEE 37401 400 Chestnut Street Tower II
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4 August 24, 1981 e?
9 %g/ q,e Mr. James P. O'Reilly, Director N
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Office of Inspection and Enforcement
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U.S. Nuclear Regulatory Commission 9
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Region II - Suite 3100 y
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Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - WATER FOUND IN ROCK ANCHOR TENDON HEAD PROTECTIVE GREASE CANS - NCR 1005 - FIFTH INTEDIM REPORT On May 23, 1979 R. W. Wright, NRC-0IE Region II, was informed that the subject nonconformance was determined to be reportable in accordance with 10 CFR 50.55(e). This was followed by our interim reports dated June 22 and November 23, 1979, March 21 and September 24, 1980. Enclosed ie our fifth interim report. Because over one year of actual testing will be required to obtain realistic results from the corrosion tests, we expect to submit our next interim report on January 7, 1982.
If you have any questions concerning this matter, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY
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M. Mills, Manager Nuclear Regc'.ation and Safety Enclosure cc:
Mr. Victor Stello, Jr., Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 s
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8109010352 810824~
PDR ADOCK 05000438
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i ENCLOSURE l
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 WATER FOUND IN ROCK ANCHOR TENDON HEAD PROTECTIVE GREASE CANS 10 CFR 50.55(e)
NCR 1005' FIFTH INTERIM REPORT Description of Deficiency Inspection of approximately 20 (10 randomly chosen on each unit) rock anchor tendon head protective grease cans indicates ground water is infiltrating up along the grouted tendon through the grout hole in tne shim stack and into the grease cans. The grease cans are filled with grease to protect the tendons and anchorheads from corrosion. Any water entering the grease cans has the potential for causing corrosion problems. No other TVA plants have a prestressed tendon system.
Interim Progress Pumping of water from the 23 dewatering holes located in the unit 1 teudon gallery floor is continuing. Drilling of dewatering holes in the unit 2 tendon gallery is scheduled to begin after the unit 2 vertical tendons are installed and stressed. After plant operation begins, all j
dewatering holes in unit 1 and unit 2 will be routinely inspected to detect any pump malfunctioning.
A problem has been encountered with the unit 1 rubber membranes and has been identified as a nonsignificant nonconformance report (NCR 1514).
The problem involves grease leaking from the membrane valve stems on 123 of the 185 membranes that have been installed in unit 1.
An investigation into the cause of the leaking valve stems involved raising three grease cans at random and inspecting the membranes. The results of I
this investigation indicated that all three tambranes had ruptured allowing grease from the grease cans to escape through the valve stems in-the membranes. Based on this information, it is assumed that the j
remaining leaking membranes have also ruptured. The primary purpose of the membranes is to monitor ground water beneath the membranes to determine the effectiveness of the dewatering system and to determine which grease cans should be inspected during the inservice surveillance.
Although the ruptured membranes will not confine the infiltrating ground l
water, if any, they can still be used to monitor ground water in the shim stack area. Therefore, based on the above information and since approximately one-third of the membranes have not ruptured, TVA will use the unit 1 membranes "as is" and will proceed with installation of.the unit 2 membranes.
Greasing operations on the unit 1 vertical tencons has just recently been completed and the membranes will be monitored every 30 days for 90 days to determine the amount of ground water, if any, that is infiltrating into the area beneath the membrane. Results of this meritoring orogram will be submitted in our next interim report.
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Before coupling the unit 1 rock anchor tendons to the vertical tendons, TVA perforcea a final visual corrosion inspection of each unit 1 rock anchor tendon bushing, buttonhead, and anchorhead. Results of this inspection, which ir.volved extensive cleaning of all rock anchor components subjected to inspection, revealed that the majority of the components showed an insignificant acount of corrosion with the remaining components showing no evidence of corrosion. All corrosion observed was classified as grade B using the Swedish Standards Institution standard SIS 05 59 00-1967. Results on this corrosion inspection will be used during the inservice surveillance to determine if additional corrosion has developed since coupling.
Requirements for the corrosion testing program have now been established ard some testing has begun; however, there are no significant test results available for reporting at this time. A timetable showing the corrosion tests and their anticipated completion dates is attached.
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- ATTACliMENT
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CORROSION TESTING PROGRAM - TIH* TABLE d
Test Completion Date 1.
Cencral corrosion rato of September 4, 1931 AISI 41h0 (anchorhead unterial) and ASTM A421 (tendon viro caterial) steels using electrochemical cethods 2.
Effect of tendon wire F.rease on September 4. 1981 the pii of neutral ground uatur 3.
Stress-ccrrosien cracking of tbrch 5, 1982 stressed AISI 4140 stcol 4.
Ger.eral cerrosion rate of March 5, 1982 AISI 4140 and ASTL A421 stcols by itzercion in a ground rater environ.5ent 5
Stress-corrosion crackina of September 3, 1982 stressed ASTM A421 steel b
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