ML19261D496
| ML19261D496 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/24/1979 |
| From: | Reinaldo Rodriguez SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Doug Garner Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7906190335 | |
| Download: ML19261D496 (2) | |
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- ~ ; SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452-3211 May 24, 1979 Of fice of Nuclear Reactor Regulations Attention
Mr. Dan Garner, Branch 4 U. S. Nuclear Regulatory Commission Wachington, D. C. 20555
Dear Mr. Carner:
Attached is a table summarizing information given to Mr. Sandy Isreal, NRC, by telephone yesterday morning concerning past turbine and feedwater initiating events.
In case one (1), the reactor tripped on high pressure 5.4 seconds following a turbine trip.
In case two (2), the reactor tripped on an overpower indication for the allowable reactor coolant flow condition.
This rep.sents a trip prior to the normally expected high reactor coolarc pressure trip due to the conservative method used for reactor ccalant flow scaling.
Cases three (3) and four (4) are turbine trips from 100% power where reactor trip parameters were not exceeded.
Case five (5) is a trip of one feedwater pump (one was out of service) from 38% power.
The initial indication of degraded flew occurred 10 seconds before the reactor trip on high pressure.
Case six (6) was a rapid reduction of feedwatei om 72% power.
The same first indication of degraded flow occurreo 9 seconds prior to the reactor trip on high pressure.
We feel the installation of the direct reactor trip on turbine trip will result in a decrease of five (5) plus seconds before the normally expected high pressure trip.
The direct reactor trip on low feedwater pump pressure will result in a similar decrease compared to the reactor coolant high pressure trip.
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R. J.
odriguez.
Manager, Nuclea' Operations g
RJR: DCB: sc 6 \\s 790619033S' 7s Attachment A'
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't ] ? E THAN 62: :02 il THE 4E
07 ;;. - 2 ; 16 A
Case Rx. Power Initiating Event Time to Reactor Trip 1
100%
Turbine trip 5.4 seconds high pressure 2
100%
Turbine trip 3.8 seconds powe r/ imbalance / flow 3
100%
Turbine trip Reactor trip parameters not exceeded 4
100%
Turbine trip Reactor trip parameters not exceeded 5
38%
Feed pumps Approximately 10 seconds tripped high pressure 6
72%
Rapid Feedpump/
Approximately 9 seconds feedwater runback high pressure 2308 170 m
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