ML20099L257
| ML20099L257 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 09/06/1995 |
| From: | GEORGIA POWER CO. |
| To: | |
| References | |
| OLA-3-A-171L, NUDOCS 9512200254 | |
| Download: ML20099L257 (2) | |
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'E EVENT REPORT (LER) f/l G ' So"M7##M,Mo!'no7',,3!!"#,7.*J.'?!
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"""*"" ~ ~"*" TIC E O F S E C R E TA R Y
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During the sEe@ftesM@ the DG on 3-30-90,~ one of the switches' (TS-19111) tYib8d and, wou.M nat..casats.:This. appeared to be a
an intermittent failure because it subsequentTy'recffanicalTy reset.
6 This switch and the leaking switch (TS-19112) were replaced with new switches. All subsequent testing was conducted withono, additional.
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Problems.
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g, A test of the jacket water system temperature tran'sfent during engine pa starts was conducted.
The purpose of this test was to determine the 5E actual jacket water temperature at the switch locations with the engine 4
in a normal standby lineup, and then followed by a series of starts F
without air rolling the engine to replicate the starts of 3-20-90.
The test showed that jacket water temperatura at the ' switch location decreased from a standby temperature of'163 degrees F to approximately j
156 degrees F and remained steady g.4..'
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Numerous sensor calibrations '(incTu' ding jacket water temperatures),
1 special pneumatic leak testing, and multiple engine starts and runs were performed under various conditions._ After the 3-20-90 event, the l d e*g a d ~ control systems of both engines have been subjected to a compr test program.).sfubsequent to this test program, DGIA and DGlB have been j
j started at least 18 times each and no failures or~ problems have i
occurred during any of these starts.t. In addition ~, an undervoltage start test without air rol1 was ponducted on 4-6-90 and DGIA started and Toaded p+ roper 1yIH J. 'Huevw, fkise%tr MwM m OG39 ruelh) in Ah*
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Based on the above facts, it is concluded that the jackefpn<J k 6n -es b.r M *e f
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i temperature switches were the most probable cause of both trips on 3-20-90.
E.
ANALYSIS OF EVENT The loss of offsite power to Class IE bus IBA03 and the failure of DGIA to i
start and operate successfully, coupled with DGlB and RAT IB being out of j
service for maintenance, resulted in Unit 1 being without AC power to both Class IE busses. With both Class lE busses deenergized, the RHR System could not perform its required safety function. Based on a noted rate of rise in the RCS temperature of 46 degrees F in 36 minutues, the RCS water would not have been expected to begin boiling until approximately I hour and 36' minutes after the beginning of the event.
Restoration of RHR and closure of the containmeat equipment hatch were completed well within the estimated. L hour and. E minutes. for the projected onset of boiling in the RCS. A review of information obtained f rom the j
Process and Effluent Radiation Monitoring System (PERMS) and grab sample analysis indicated all normal values.
As a result of this event, no increase in radioactive releases to either the containment or the environment occurred.
9512200254 950906 92 PRCUECT 057514 PDR ADOCK 05000424 J2 O
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