ML19322C473
| ML19322C473 | |
| Person / Time | |
|---|---|
| Site: | Crane, Davis Besse  |
| Issue date: | 07/25/1978 |
| From: | Murray T TOLEDO EDISON CO. |
| To: | |
| References | |
| TASK-TF, TASK-TMR TT-3.3, NUDOCS 8001170797 | |
| Download: ML19322C473 (2) | |
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4e IllE TCLEDO EDt:ON COMPANY FILE ELEP' HONE CALL DOCUMENTATION TT 3.3 um acute To:
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Toledo Edison' Company Terry Murray coveau ric acam:aricN m uaot to:
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Bill Spangler 35W Lynchburg 2,
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lONFE AENCE CALL canTIES Fred Faist, Chuck Domeck, Ed Kane, Dick Deefars, Bob Ninks, Ray Lukon, 3,
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iTATIONiUNIT DATE TIME D-B #1 July 25,
, 78 1430
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1977 Tcrry Murray reviewed the question that was discussed, i.e., on the November 29th Event I
whtn the pressuri:er level dropped below indicated range, how can we, Toledo Edison, rationali:: $
continued operation given the fact that during this event pressuri:er level did go off scale.
Wa must also consider that the second auxiliary feedpump did not start until later. The
[transientanalysisindicatesthatweshca'dnotloselevelsbutinactualexperiencewe did, hh t is the difference between the two? What have we done to correct the situation?
Bob Winks of 35W reminded us that the main steam safety valves had a very large effect on the transient that was observed in the November 29th Event.
During that event,stesa
-. pressure was allowed to drop to somewhere between 940-950 pounds.
Based on the data i observed'during the 75*4 turbine trip in April of this year, we know that the adjustments
! that we made in the interim now prevented steam pressure from going below 975.
Since the April 2nd turbine trip test, we have in fact made further adjustments to better refine the l
l steam pressure control transient. Now we expect that steam pressure will be maintained neuen g ' higher than the 975 because there were several valves that had to have their setpoint adjusted upward. The improvements that were made as a result of these upward setpoint adjust-I m:nts can be demonstrated by the fact that during the turbine trip test, we did in fact main-
.tain pressuriter level.on scale.
Another significant item that was brought out in the discussion with those people was that if in fact both auxiliary feedfumps did come on simultaneously as designed, and if there was a significant difference as a result of the second feedpue.p coming on, that the expansion of F. Faist,C, Domeck, Section Heads, L. E. Roe, J. S. Grant, Don Lee FO M CC"" N j
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'e TELEPHONE CALL DCCUMENTATION Terry Murray/ Bill Spangler Conference Call July 25, 1973, 1430 Page 2 g
the pressurizer steam bubble into the No. 2 Loop, i.e., the Loop that is connected M the pressuri:er, that this would only give you a vapor lock 3for affect the natural circulation in the No. 2 Loop. The No.1 Loop would still be available for natural circulation and one loop is sufficient to
[removethedecayheat.
Third item directly related to this is that the review of the strip charts and plots for the November 29th Event indicate that there was only approximately a minute difference in the time that the two pumps were actuated and that during this period of time the pressuri:er level was still falling and that pressurizer decrease effect was a result of both auxiliary feedpu=ps feeding steam generators.
It was agreed that;our position.is one that we have made adjustments to the
! main steam safety valves which would greatly reduce the shrinkage that we see "in the pressur$ ter in an event like this.
Second point is that if both aux feedpumps do come on and you get steam blockage, it would only affect one loop.
The other loop would be available for decay heat removal.
The third point is that the actual difference in time between the two auxiliary feedpumps in the November 29th Event was so slight that in fact the. effect that we saw was a result of both auxiliary feedpu=ps.
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