ML20137Q999
| ML20137Q999 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/06/1995 |
| From: | Mark Miller NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Landis K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20137Q937 | List: |
| References | |
| FOIA-96-485 NUDOCS 9704110196 | |
| Download: ML20137Q999 (1) | |
Text
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i gS'bC,.36 From: Mark S. Miller (MSM)/ k To:.
' KDL
. - t Lmd DL5 I O ll Date: Monday March 6, 1995 12:37 am '
Subject:
St. Lucie 1 Loss of. Shutdown Cooling' Saturday night. Unit 1 experienced an approximate 8 minute loss of shutdown cooling. The event occurred as the licensee was securing the A SDC train.
The A pump had been secured and the operator was completing his procedure when the operators noted an increase in primary system pressure (the unit was solid on letdown pressure control at the time).
In response. they secured charging and B SDC and increased letdown flow indirectly by dialing down the letdown pressure control setpoint. This returned primary pressure to normal.
They then returned B SDC to normal. 'In the aftermath, they found that a B SDC hot leg suction isolation was closed.
The licensee is going down two paths with respect to root cause.First.
they're ex)loring the posibility that this could have been operator error.
In securing t1e A SDC train. the operator was at the point where he would have secured the A hot leg isolation. The licensee thinks he may have. shut the B isolation instead, thus starving the B pump for suction, removing SDC and leading to a sight heatup of the primary, resulting in the pressure increase they saw. Based upon strip chart and sequence of events output. along with Lwhere they were in the procedure, this argument has merit.
The second option is that some electrical fault caused the valve to go closed.
They've identified (on control wiring diagrams) one possible point where a ground might lead to a closure. This is less likely, but they're trying to be thorough.
I'm continuing to follow it and I'll let you know what happens.
I'm E-mailing this (and faxing it too) cuz it's dark thirty (I was trying to follow mode changes and possible crit, but it's been delayed pending resolution of this issue) and I don't expect to be in until late Monday morning.
As regards other stuff. I expect to get the report out Tuesday.
I realize we're closing in on SPPR. and I've done some initial marking up of the paper for that, but I'd like to finish the report first. After we get the report out. I'll spend as much time here as necessary to get the SPPR stuff done by Wednesday early Thursday at the latest. This su startup tommorow (...and with my third hand...'). pposes an uncomplicated To that end. I d like to dedicate Bob to getting his re) ort feeders done on Monday, and we can work together Tuesday to get the SP)R stuff done.
I plan on following the startup, currently scheduled for 1500. tommorrow, but if Bob gets 'done. I should have enough time to finish the report tommorrow night.
Call me at home'if you need any more info (407-878-7107). Otherwise. I'll talk to you probably 1100.
' Nite.
CC:
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9704110196 970327 DE 485
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l From:
Mark Miller / f/7 To:
CAJ CSOLI A% E.LL Date:
10/31/969:02am
Subject:
Criticality Monitoring Letter I read the NRR letter on criticality monitoring that was copied to us and I have a question. in discussions with our PM and the author, it became clear that when St.
i Lucie comes in for an exemption to 70.24,' they'll receive it and, in fact, they had one pre-op that wasn't subsumed into the operating license, if this is the case, shouldn't the proposed NOV be a vio of minor safety significance? I looked at the criteria in the Enforcement Manual and it seems to fit.
i CC:
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