ML19261F362
| ML19261F362 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/01/1977 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| GQL-0754, GQL-754, NUDOCS 7910250824 | |
| Download: ML19261F362 (3) | |
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M5TROPOLITAN EDISON COMPANY ::.asic:ur:c micu =u:u:urur::s cce=cu ric : l POST OFFICE BOX 542 REAOlNG.PENNSYLVANI A 19603 TELEP'40NE 215 - 929-2601 Jun.: 1, 1977 GQL 075h
.v. J. P. O'Reilly, Director e
Office of Inspection & Enforcement, Region I U. S. Nuclear Regulatory Co==ission 631 Park Avenue King of Prussia, Pa.
19h06
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 Docket No. 50-289 Operating Lice:::: Nn. DPR-50 Enclosed please find the results of the testing requested in I.E.
Circular 76-06. As stated in our letter of Dece=ber 29, 1976, this reply is within the time limit of sixty (60) days of completion of the refueling outage.
Sincerely, w
J. G. Herbein Vice President JGH:DGM:j=r Enclosure eP e
1482 110 7910250 0
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SUWJGY PEPCRT OF EXAMINATICNS A'ID EVALUATION OF RESULTS IN RESPONSE TO IE CIRCUIAR 76-06 TMI UNIT #1 Ahstract A program of chemical analysis, pressure testing, and ultrasonic examination has produced no evidence of stress corrosion cracking nor the conditions necessary for stress corrosion cracxing in stainless steel piping with lov flow or stag-nant borie acid solution.
Scope This report covers the results of chemical analysis performed from May 1976 to April 1917 on five systems containing stagnant or lov flow boric acid. Also, pressure testing on the Reactor Building Spray system was perfor=ed on Merch 17 to 18, 1977, and ultrasonic exa=inations on the Reactor Building Spray system were perfor=cd on April 11, 1977 Testine I.
Chemical Analysis The highest concentration of chlorides for each sa=ple source during the testing period is listed below. A conplete set of results for this period is available for inspection at the plant site.
Hizhest Measured Concentration of Chlorides From May 1976 To April 1977 Sample Source Concentratien, ppm Date Decay Heat System 0.4.
5-12-76 Borated Water Storage Tank 0 765 6-lh-76 Reactor Coolant Bleed Tanks 0.h2 11-26-76 Core Flood Tanks 0.26 8-16-76 Spent Fuel Fool 0.30 30-16-76 II. Pressure Testing On March 17 to 18, 1977, a pressure test of the Reactor Building Spray sys-tem was conducted in accordance with the provisiens of Articles IWA-5000 and IWC-5000 of the 197h Edition of Section XI of the ASME Boiler and Pressure Code. TMI-1 Special Operating Procedure #h76 was used to perform this test.
As required therein, each of the two loops of the system vas, in turn, held at nor=al operating pressure for four hours, then ' visually inspected. No leakage from pipe, fittings or velds was detected, nor was there any unaccept-able leakage of any kind. The test pressurized Reactor Building Spray pip-ing from the Borated Water Storage Tank, up to the Reactor Building isola-tion valves (ES-V-1A/3), through the recirculation loop, and back to the Bor-ated Water Storage Tank.
Procedure and data are available for inspection at the plant site.
III. Ultrasonic Tee Lag Ultrasonic ex alnation of four velds in the Reactor Building Spray system was perfor=ee on April 11, 1977 The four velds exa=ined are located on either
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IE CIRCULAR 76-06 PAGE 2 end of the first 90 eltov off cach of the two pu=p discharges. The two velds in the "A" circuit are designated 76-06 -1 and 2 (in crder of flow direction), and the two velds in the "3" circuit are designated 76-06-3 and h (also in order of flev direction). These velds were selected on the basis of stress, probable exposure to chlorides and accessibility.
The inspecticn was performed in accordance with TMI-1 Surveillance Prece-dure 1300-IE " Manual Ultrasonic Examination of Reacter Coolant and Asscc-iated Piping Welds".
Exssined areas covered a distance of two (2) inches on both sides of each veld.
No indication of stress corrosion cracking er any other failure = ode was detected by this examination. Procedure and examination results are avail-able for inspection at the plant site.
Evaluation I.
Chemical Ana'.ysis It is well established that stress corrosion cracking does not occur when ch16 ride
- encentraticas are below ten ppm.1 Since none of the above maxi-cum concestrations exceeded even ene pps, it has been de=enstrated that the conditie;s for stress corrosion cracking do not exist.
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Monitoring for chlorides vill be continued.
In the event that a threshold of ten ppm chloride concentration is exceeded at so=e time in the future, special testinC of the piping involved vill be considered at that time.
II.
Pressure Testing Successful performance of the pressure test described above has demenstrated the integrity of the Reactor Building Spray system.
III. Ultrasonic Testing The axamir.ation described above has verified that stress cerrosion cracking does not exist in the particular velds inspected. Further, since the velds to be examined were selected on a " worst case" basis, (the examined velds are on a 90 elbov just off the pu=p discharge and are, therefore, relatively highly stressed, and they are al=ost constantly exposed to stagnant boric acid because they are at a low point in the system) this result provides added assurance of the integrity of the entire Building Spray system.
1.
Iatanisien and Staehle " Stress Corrosien of Iron-Nickel-Chremium Alloys"-
Proceedings of the Conference on Fundamental Aspects of Stress Corrosion Cracking - September 11-15, 1967 - ohio State University.
Copyrighted 1969 - National Association of Cerrosien Engineers.
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