ML17252B012
| ML17252B012 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 11/15/1972 |
| From: | Worden W Commonwealth Edison Co |
| To: | Anthony Giambusso US Atomic Energy Commission (AEC) |
| References | |
| Download: ML17252B012 (2) | |
Text
e Regulatory:
-* -.. ~..........
Commo_nwealth Edison Company 72 WEST ADAMS STREET
- CHICAGO, ILLINOIS-
~,.., lleply fo, P
T 0 FF ICE B 0 X 7_6_J
- CH IC AG 0, I LL IN 0 IS 6 0 6 9 0 Dresden Nuclear power Station R. R. #1 ro ~&l.9 Morris, Illinois'
- 60450
~I
- 911 T November 15, 1972 Mr. A. Giambusso Deputy Director for Reactor Projects Directorate of Licensing Washington, D.C.
20545
Subject:
Lie.ense DPR-25 Dresden: Nuclear Power Station Section 6.6.C~l of the.Technical Specifications Unit\\
Dear Mr. Giambusso:
This is to report a condition relating to the operation of the station, when, during local leak rate testing of primary containment rubber seated ventilation valves, the valves associated-with primary containment system-penetration X-1_26, -~a leakage rate greater than.
that specified for a single penetration.':*
. PROBLEM AND INVESTIGATION At 1100, Ocbober 25, 1972, with the *reactor at a power level of 805 Mwe, local leak rate. tests were being conducted on the primary containment.rubber seated ventilation valves.
These tests are required each refueling outage~ but presently are conducted on a three month frequency due to previously experienced problems with deterioration of the valves' rubber seats.
On the first test of the valves associated with penetration X-126, the leakage was 129.9 scf/hr, which exceeds the leak rate specified for a single penetration (29.34 scf/hr).
These valves were last tested on July 19, 1972 and had a leakage of 14.7 scf/hr.
Upon visual inspection of valve 3-1601-22, cracks in the rubber seat were observed.
A blind flange was placed OV-er the penetration to insure adequacy of primary containment.
At 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> another test was run and the leakage was 40. 75 scf/hr.
Minor leakage was no.ted around the blind flange. - This flange was tightened: and the leakage was reduced to 32.28 scf/hr with no leakage around the blind flange.
The other rubber
-seated valves on Units 2 and 3 were all tested with satisfactory results.
Mr. November 15, 1972 In the initial integrated leak rate test of the Dresden Unit.#3 primary containment, which was conducted fr0m August 22, 1970, through August 26, 1970, the total leakage Lm(48) out of the primary containment was calculated to be 0. 232 weight percent of the--contained air.
Using the latest available leak rates, including the 32.28. scf/hr for penetration X-126, the total leakage Lm(48) from the primary containment. is now 0.362 weight percent, which is well within the Technical Specification limit of 1.6 weight p~rcent of, the contained air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
CORRECTIVE ACTION As soon as practical, all primary containment rubber seated valves sim~lar to and including.th~. St;ibje,~t valve,.will be.removed, and. SE!nt to the manufacturer to be reseated-1wlth ~rCimproved seat mater;ial.
These valves will continue to be checked "on a three. month basis in the.,int,erim
- WPW:sdb Sincerely,
- w. P. Worden Superintendent