Another shutdown at Limerick Plant

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Daily Events Report

Another reactor scram and shutdown at Limerick.

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TURBINE TRIP FOR UNKNOWN REASONS RESULTING IN AN AUTOMATIC REACTOR SCRAM The following text is a portion of a facsimile received from the licensee: "At 1631, Unit 2 received a main turbine trip signal and [an automatic]reactor scram [from 100% power.] All systems operated as designed. The investigation into the turbine trip is ongoing. There was no release of radiation to the environment."

The licensee stated that all rods fully inserted upon receipt of the reactor scram. There was no pressure transient. Reactor vessel level decreased to approximately +10" and recovered to approximately +30". (The reactor scram setpoint is at +12.5", and the emergency core cooling system actuation setpoint is at -38".) There were no engineered safety feature (ESF) actuations (other than the reactor scram), and none were required. The licensee also stated that there were no turbine-related maintenance or surveillance activities ongoing at the time of the event. An AC bus outage was commenced the previous night. The unit is currently stable in Mode 3 (Hot Shutdown). Normal condensate and feedwater is being supplied to the reactor vessel, and steam is being dumped to the main condenser. There was no adverse effect on containment parameters. The licensee notified the NRC resident inspector as well as applicable state and local agencies. ******************** UPDATE AT 2338 ON 01/08/00 FROM PHIL CHASE TO LEIGH TROCINE****************** The licensee updated this event notification to clarify that there was an ESF actuation. The end of cycle recirculation pump trip breakers opened as designed on the turbine trip. The NRC operations officer notified the R1DO (Meyer).

-- Cin (Cinlooo@aol.com), January 10, 2000

Answers

Thanks Cin.

Interesting to note on same page that Comanche Peak had lost offsite power source.

-- (pigs@do.fly), January 10, 2000.


John Krepasky, if your still out ther -- hope so -- I would REALLY welcome your two bits on this. I presume that standing alone it is unremarkable, statistically; and perhaps it's unremarkable that its twice in a week or two that the Limerick mPlant has scrammed or been put on hot standby. With respect, are the number of events pushig any nearer your threshhold of concern?

-- (squirrel @huntr.com), January 10, 2000.

EEEK! Comanche Peak lost off-site power source? HOWCUM? IS it down or on gennies? will go check.

-- (squirrel @huntr.com), January 10, 2000.

Momentary outage by the looks of things.

However. the RIver Ben Lousiana Plant also appears to be shutdown due to "unusual and unexplained cavitation and vibration in the high pressure core spray thingamajig" and if they can't5 find the cause and fix the high pressure core thingambob the reactor goes on cold shutdown in 14 hours.

-- (squirrel@huntr.com), January 10, 2000.


Is there a link for archived daily events on the NRC site?

I hadn't looked at the NRC site for several days until today. The Plant Status Report page has had a lot of new shutdowns/scrams since. Wasn't aware that Salem 1 did a hot shutdown on Jan. 6. It refers to event #36567, but the daily report site only goes back to the 7th.

If there's no access to archives on NRC site, maybe we should keep track of events here.

-- (pigs@do.fly), January 10, 2000.



Oh and this one from Jan. 8 has no event number but doesn't appear to be routine shutdown:

COOPER 1 0 01/08/00 Cold Shutdown REDUCED POWER DUE TO AUX COOLING SYSTEM LEAK INTO THE DRYWELL

-- (pigs@do.fly), January 10, 2000.


This appears to be the second scram in less than 2 weeks for Limerick 2. The 1st was on Dec 31, which read:

Hot Shutdown. REACTOR SCRAM DUE TO MAIN TRANSFORMER FAILURE. SEE EVENT 36553.

Is this normal?

-- Spindoc' (spindoc_99_2000@yahoo.com), January 10, 2000.


As of this morning, there were 11 plants at 0% power. I'm not positive, but I'd say this odd.

-- Cin (Cinlooo@aol.com), January 11, 2000.

BTW, the PLANT STATUS REPORT, as of 0012 a.m. 1/11/2000,

http://www.nrc.gov/NRR/DAILY/psr.htm,

still dated 1/3/2000, reads:

LIMERICK 2 30% Power Operation INCREASING POWER

Again, is this normal operation? Just asking....

-- Spindoc' (spindoc_99_2000@yahoo.com), January 11, 2000.


As noted on:

http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=002HWW

The current Plant Status Report, as of NOW, 0106, 1/11/2000, has reverted to the 1/3/2000 report (vice 1/7/2000), and doesn't include the above current Limerick2 status, as described in the Daily Events Report: (http://www.nrc.gov/NRR/DAILY/der.htm).

So, in summary, we have a HOT SHUTDOWN due to MAIN TRANSFORMER POWER on 12/31/1999.

We have a report of an increase in power from 30% on 1/3/2000.

We have a report of 100% power on 1/7/2000.

And we have a report of a TURBINE TRIP FOR UNKNOWN REASONS RESULTING IN AN AUTOMATIC REACTOR SCRAM Oon 1/10/2000.

The latest report is from the DAILY EVENTS REPORT, linked above.

Meanwhile, the PLANT STATUS REPORT has reverted to an outdated report, dated 1/3/2000.

What is going on, please?

-- Spindoc' (spindoc_99_2000@yahoo.com), January 11, 2000.



Don't know.

Immediate cause was the loss of the turbine - and those things don't normally trip out like that. (That is, regardless of whether this was nuclear or fossil-fuel, tripping a turbine shuts down the plant. For a nuclear, shutting down suddenly (like this) includes an automatic reacotr scram - so the protection worked as intended.)

Question is: why didn't the turbine work as intended?

The regular nuclear reports I review won't have thse incidents until much later (March issue perhaps) - but I'll see what other sources report.

-- Robert A Cook, PE (Marietta, GA) (cook.r@csaatl.com), January 11, 2000.


No, actually, it isn't odd for the same reactor to have SCRAMS a few days apart.

I found several that had shutdowns during the powerup after a shutdown....Braidwood 2 went down 1 day after going down in April last year. Ginna 1 wen down 4 days after going down in April last year.

San Onofre 3 went down two days after going down in May of last year.

-- John H Krempasky (johnk@dmv.com), January 11, 2000.


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