ML20084D469
| ML20084D469 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/01/1973 |
| From: | Worden W COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 3619, 417-73, NUDOCS 8304120011 | |
| Download: ML20084D469 (2) | |
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_ C f@'d' Ccmmon;pjlth Ediscn y
v One First Na6chal Plaza, Chicago, titinois 50-237
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%'4 Address Rep!y to: Post Ofhce Box 767 l
W Chicago, lihnois 60690 0-2 i
WPW Ltr.#417-73 Dresden Nuclear Power Station R. R. #1 9
Morris, Illinois 60450 GNx June 1, 1973 o
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Mr. A. Giambusso 4.,
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Directorate of Licensing
@'(7 U. S. Atomic Energy Commission Washington, D. C.
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SUBJECT:
LICENSE DPR-19 & 25, DRESDEN NUCLEAR POWER STATION, UNIT #2&3 l
SECTION 6.6.B.3 0F THE TECllNICAL SPECIFICATIONS.
Dear Mr. Giambusso:
This is to report a condition relating to the operation of the unit in which on May 24, 1973, the Unit #3 and Unit #2/3 emergency diesel generators tripped on high temperature. This occurrence was telephoned to !!r. Hugh Dance of Region III of Regulatory Operations at 1340 hrs. on May 25, 1973 and followed up by~ telegram one hour later.
PROBLEM AND INVESTIGATION On May 23, 1973 the Units 3 and 2/3 emergency diesel generator cooling water flow was reversed as requircd by procedure 6600-S-I which is conducted during each maintenance outage.
On May 24, 1973, surveillance testing was conducted on both diesel generators in preparation for going to the " Refuel" mode from the " Shutdown" mode for control rod scram testing.
The units #3 and #2/3 diesel generators tripped on high teinperature at approximately 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />. This violated section 3.9.D of the Unit #3 Technical Specifications and section 3.9.A.2 of the Unit #2 Technical Specifications.
Investigation revealed that the cooling water flow valve lineup was incorrect. The resulting low flow of cooling water' caused the diesel generators to trip on high temperature. This incorrect valve lineup was the resul.t of an unclear procedure.
The diesel generators were inoper-abic for approximately 25 minutes while the lineup was corrected. The diesel generators were subsequently tested and run for one hour to verify proper
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_ CORRECTIVE ACTION The surveillance procedure is only used during. maintenance outages and thus is used at infrequent intervals.
The short coming of_this proced,ure had not been apparent until this incident.
The procedure will be revised so (D'h J
pypv B304120011 730601 J/
PDR ADOCK 05000237
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s PDR COPY SENT REGION _
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l Junt 1, 1973 Mr'. A. Giambusso res, *I I i
thatthecorrectvalvelineupwillbehplicitlystated.
This revision will be completed during the next 60 days. This occurrence does not pose any probicms other than to revise the procedure.
No plant equipment mal-function was involved.
There were no effects on the safety of plant personnel or the public during this situation because Unit #3 was in the shutdown mode, no work was in progress that had the potential for draining the vessel, and a core or containment cooling system was not required.
Secondary containinent power requirements could have been met by the Unit #2 diesel generator. The operation of Unit #2 was such that sufficient power was availabic from other sources.
Since power was available to the 345 KV switchyard, and from the 138 KV system through a 4160 volt bus tie, and the fact that one diesel (the Unit #2 diesel) carries suf ficient engineered safeguards equipment to cover all breaks,there was no compromise of public safety.
Sincerely, W. p. Worden Superintendent WFW:do cc: WPW Ltr. File o
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