ML17252A974
| ML17252A974 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/01/1973 |
| From: | Worden W Commonwealth Edison Co |
| To: | Anthony Giambusso US Atomic Energy Commission (AEC) |
| References | |
| WPW Ltr .#417-73 | |
| Download: ML17252A974 (2) | |
Text
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- Commom91th Edison.
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One First National Plaza, Chicago, Illinois egulatory
- Address Reply to: Post Office Box 767 Chicago, Illinois 60690 50-237 50-249 WPW Ltr.11417-73 Dresden Nuclear Power Station Mr. A. Giarnbusso Deputy Director for Reactor Projects Directorate of Licensing U. S. Atomic Energy Cormnission
- washing*ton, D. -c.
- 2054'5 R. R. Ill Morris, Illinois June 1, 1973
SUBJECT:
LICENSE DPR-19 & 25, DRESDEN NUCLEAR POWER STATION, UNIT 112&3 SECTION 6. 6. B. 3 OF THE TECHNICAL SPECIFICATIONS.
Dear Mr. Giambusso:
This is to report a condition relaxing 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 c>"cc.urr.ence -.was* telephoned to Mr. Hugh Dance of Region III of Regulatory Operations at 13.40 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 required by procedure 6600-S-I which is conducted during each maintenance outage.
On May 24.,,.-1973, surveillance testing was conducted on both dtesel genera.tors in preparation for going to the "Refuel' 1 mode from the "Shutdown" mode for control. rod scram testing.
The units #3 and 112/3 diesel generators tripped on high temperature 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 113 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 result of an unclear procedure.
The diesel generators were inoper-able for approximately 25 minutes while.the lineup was corrected.
The diesel generators were subsequently tested and run for one hour to verify proper operation.
CORRECTIVE ACTION The surveillance procedure is only used during maintenance outages and thus is used at infrequent intervals.
The short coming of this procedure had not been apparent until this incident.
- The procedure will be revised so 3619
~
~r: that the correct valve lineup will be explicitly will be completed during the next 60 days.
This any problems other than to revise the procedure.
function wa.s involved.
- June l, 1973 stated.
This revision occurrence does not pose No plant.equipmentrnal-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 containment power requirements could have been met by the Unit #2 diesel generator.
The operation of Unit #2 was such that sufticient power was available.. from other sou-rces.
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 sufficient engineered safeguards equipment to cover all breaks, there was no cornpromis.e of public safety.
Sincerely,
.~v\\D~
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.... w. P !.. word.en :'
Superintendent*
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WPW Ltr. File