ML20151C185
| ML20151C185 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/10/1973 |
| From: | Reeves D JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| References | |
| AO-73-19, NUDOCS 8103041008 | |
| Download: ML20151C185 (3) | |
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THIS C9CUMEN1-'CONTAINS ABNOURL OCCURRENCE POOR QUALITY PAGES
'A..,.v REPORT NO, 73-19
SUBJECT:
Violation of_ the Technical 6pecification, paragraph 3.7. A.2, in-that although both startup transfomers were energir.ed to carry power to-the station 4160V' AC busos, neither transformer-could be considered operab1'e due to an improper setting on the C base differentia 1'monit-oring; relay,
- Additionally, this event is considered to be an 'abnomal occurrence as defined in the Technical Specifications,A paragraph 1.15G, in that proper procedural controls were not implemented with respect to pro-tective relay testing, which resulted in the development of an unsafo condition in connection with.the operation of the plcat.
Notification of this event, as required by the Technical Specif;ications, paragraph 6.6.2,a, was made to AEC Region I, Directorate of Regulatory Operations, by telephone on Saturday, September 8,1973, at 10:15 a.m.,
and by telocopier on Monday, September 10, 1973, at 1:30 p.m.
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SITUATION:
l A plant shutd.own had progressed to the point where, with electrical
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output at approximately 90 Mio, a transfer of station. loads from the Auxiliary Transfor:nor to the Startup Transformers was attempted. When a closing signal was applied to the S1A breaker, a loss of power occurred tho'the "1A" 4160V AC bus, which among other things caused two circula-tory water pumps, three reactor recirculation pumps and the operating i
~ condensate and feedwater pu ps to trip.
Diesel Generator #1 started El030$oog
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j Septceher 8, 1973 Abnores1 Occurrenco s
Report No. 73-19
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in the " Fast Start" mode, reenergising tho' 4160V "1C" bus and the req-
'An attempt. was made tu start the D quisite safeguard power supplies,
'and C condensate pumps, but before either purp could be started, the-Automatic transfor. todhe
.g reactor scracacd due,to low water' lev'el, _
but 14ter in atte pting to start a m
' SIB transfortter was accosplished,.
condensate pump pwered from the "10" 4160V bu7, SIB tiipped initia 9
Tho'second CRD pucp the " Fast start" sequence on Uleiol Generator #2, was started to-assist in monitoring rea'ctay water l'evel which dropped isolated to prevent The reactor w M to 9 feet above the active fuel.
initiated as water in entory loss and the ecergency condensers were v
l The point at which reactor. isolation needed to remove tlecay heat.
occura and the emergency cooling systern is initiated wm ne,t, reac c
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,etting of the current trans-
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The problem was traced to an incorrect l
CAUSE:
former ratio matching taps for the c phase differential relay on bo^
In'attetapting to either' carry a sicedblo load or startup transfo mers.
start a large loud, a differential fault was sensed, tripping the out-t put breakers.
PM01 A1, fd.TIOK:
The curront transfomer ratio ett:hing taps w'ere set up properly The company Relay Departcent
,3 station loads wore returned to norraal.
was contacted and load-checks were conducted in each of the startu if y
transformor phase differential relays. All checks were sat s actor,
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k-AbtlordalOc'cuxTenco 3-Septer:her 8,1973 Report no; 73-19 a
i sArr.TY SIGNIFICANCE:
The significance of this event is that tho designed redundancy of i
1 pcuor supplies for the station 4160V buses was not present and, in fact, had not been pree.ent 9.ince July 30, 19734when the rolay test was inade. iWcVer, both dicSel f.enerators did function properly upon the loss of power. Consequently, plant safety was not endangered.
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Prepared by: __
__ o. - /_ b a s g Date:
Septcmber 10; 1973
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