ML20087L577
| ML20087L577 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 06/25/1974 |
| From: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20087L573 | List: |
| References | |
| NUDOCS 8403270281 | |
| Download: ML20087L577 (4) | |
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N!,l.ia June 25, 1974 Mr. John F. O' Leary, Director Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C.
20545
Dear Mr. O' Leary:
DOCKET NO. 50-266 POINT BEACH NUCLEAR PLANT LEAKAGE TESTS OF ISOLATION VALVES In our letter to you of May 3, 1974, we reported details concerning test of containment isolation valves for Unit 1 at Point Beach Euclear Plant.
At that time ve advised you that 70% of the containment isolation valves had been leak.
tested and testing of the remainder was in progress.
Wo indi-cated that should other valves be found to have leakage in ex-cces cf 2000 c / min, vu uculd advice you of cuch event.
We have now completed the containment isolation valve leakage tests and Unit 1 at Point Beach Nuclear Plant has been returned to service.
This is to report that five (5) valves fall into the category of having exhibited a leak rate in excess of 2000 cc/ min. when initially subjected to a local air pressure test of 60 psig.
The test performanco of these five valves is describcd in the attached table.
Specific comments on cach valve testing are as follows:
1.
The valve seat uas found to have been scarred by some foreign material.
The seat was repaired.
2.
The valve was full of carbon dust from-the vanes of the carbon.vano type radia-tion monitor pump.
The pump has been replaced with a water vano type pump to prevent a recurrence of the problem.
All valva parts were cleaned.and reinstalled.-
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< s Mr. John F. O' Leary June 25, 1974 3.
It was not a requirement to test this valvo prior to the issuance of 10 CFR 50, Appendix J.
Therefore, this was the first periodic test of the valve.
The closing spring of the valve was adjusted to give a greater closing force to correct the leakage.
4.
Fine powdered dessicant was found to be pre-venting the valve from closing tightly.
Fur-ther investigation disclosed a burst filter on the discharge side of the instrument air dryer, this permitting the fines of the dessicant to carry through.
The valve parts were cleaned and replaced and all instrument lines were blown down to remove all traces of dessicant.
The burst filter has been re-placed.
5.
Rust on the inside surface of the pipecarried forward tc the area of the isolation valve and ptuvenLed ils Llyht meaLiay.
The valve was cleaned and returned to service.
It should be noted that three of the above valves are check valves.
Check valves can normally be expected to seat more tightly when the closing pressure is applied quickly.
The appli-cation of closing air during a test is by means of a small dia-meter test fitting.
Pressure buildup is therefore slow and this is not conducive to tight closing of this type of valve.
Each of the above valves is part of a closed system outside containment, except item 3, and leakage to the atmosphere could occur only if a pipe break in one of the systems existed outside the containment.
In addition, each of the above valves has a'second containment isolation valve and in every case, the second valve demonstrated an acceptable level of leak tightness.
The actual contribution of leakage from these valves is measured along with all other sources of leakage'from the containment dur-ing the type "A" leakage test of the containment.
This test indi-cated that the actual measured leakage from all sources was 53%
of the allowable operational leak rate.
It is concluded.that the leakage of the above valves did not contribute significantly to the measured leakage of the containment and a hazard to the health and safety of the public~did not exist.
l
Mr. John F. O' Leary June 25, 1974 A full report of the type "A",
"B" and "C" tests con-ducted during the Unit 1 second refueling shutdown, April 6, 1974 through May 26, 1974, is being prepared and will be filed sepa-rately as required by Section V.B of 10 CFR 50, Appendix J.
Very truly yours, f
(,4,U Sol Burstein Execu ive Vice President Enclosure
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Init. Lkg.
Date of Final Lkg.
Date of Penetration i Valve #
Piping System cc/ min Test cc/ min Test 1.
X-1 3200B Containment Gas 2,598 4/20/74 91.5 5/13/74
& Particulate Monitor Supply 2.
X-2 Check Containment Gas 131,674 4/24/74 0-5/19/74 Valve
& Particulate Monitor Return L
3,,
.9 1698 RCDT Pump Suc-11,000 4/21/74 746 5/18/74 tion Linc 4.-
333 Check Instrument Air 9,621 5/12/74 786 5/18/74 Valve to Containment 5.
33C Check Service Air to 90,000
'3/28/74 783.2 5/11/74 3W Valve Containment me 4
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