ML17252A530
| ML17252A530 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/21/1974 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | O'Leary J US Atomic Energy Commission (AEC) |
| References | |
| BBS Ltr.#453-74 | |
| Download: ML17252A530 (2) | |
Text
Commonwealth Edi
- One First National Plaza, Chicago, Illinois 1illares"¥ Reply to: Post Office Box 767
- Chicago, Illinois 60690 BBS Ltr.1453-74 Mr. J. F. O'Leary, Director Directorate of Licensing
- u. s. Atomic Energy Commission Washington, D. C.
20545 5o-2'49
SUBJECT:
LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3, REPORT OF ABNORMAL OCCURRENCE PER SECTION 6. 6. B. 1 OF THE TECHNICAL SPECIFICAnONS.
FAILURE OF MAIN STEAM LINE DRAIN VALVE 3-220-2.
Reference:
Notification of Region 111 of ABC Regulatory Operati Telephone: Mr. ~. Maura, 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> on June 17, 197 Telegram: Mr. J. Keppler, 1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br /> on June 17, 1
Dear Mr. O'Leary:
This letter is to report a condition relating.to the unit at about 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on May 22, 1974.
At that time, the breaker for main steam line drain valve* 3-220-2 tripped repeatedly.
malfunction is contrary to section 3. 7.D. l of the Technical Specifications which requires that all isolatio.n valves listed in Table 3.7.1 be opera-tional during power opet;ations.
PROBLEM On May 22, 1974 main s*team line drain valve 3-220-2 failed to operate correctly.
While closing the valve in order to perform local leak rate testing, the supply breaker tripped!',repeatedly.
Several breaker resets were required before the valve could be fully closed. At the time of the occurrence, the reactor mode switch was in the "Refuel" position, with thermal power at zero megawatts.
INVESTIGATION An investigation into the cause of the breaker trip revealed that the problem was associated with the valve motor.
The motor was then removed and inspected.
The inspection revealed the armature windings were burnt and shorted.
REGULATORY DOCKET FILE COPY
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Mr. J. F '°'* Q ~Lttiiry CORRECTIVE ACTION -- -------
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June 21, 1974 The immediate corrective action taken was to reset the breaker and attempt operation until the valve reached the fully closed position.
Additional corrective action was taken after it was determined that the valve motor was faulty.
To correct the condition and to return the valve to service, *a replacement motor was installed. The failed motor was then sent out to be repaired.
Since this is the first failure of this type in regards to this valve, the corrective action taken at this time is considered satisfactory.
EVALUATION The failure of the 3-220-2 valve to operate properly did not place the safety of the plant or public in 'jeopardy. At the time of the occurrence, the unit was in the refuel mode and thermal power was zero.
Also at the time the 3*220-2 valve failed open, the upstream isolation valve 3-220-1 was operable. In addition, all safety systems were operable at the time of the failure.
Sincerely.,
BBS: TEL: do
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